Diamond
A scattering of round-brilliant cut diamonds shows off the many reflecting facets.
General
Category	Native Minerals
Chemical formula	C
Identification
Molecular Weight	12. A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes The molecular mass (abbreviated m of a substance, more commonly referred to as molecular weight and abbreviated as MW, is the Mass of one 01 u
Color	Typically yellow, brown or gray to colorless. Less often in blue, green, black, translucent white, pink, violet, orange, purple and red. [1]
Crystal habit	Octahedral
Crystal system	Isometric-Hexoctahedral (Cubic)
Cleavage	111 (perfect in four directions)
Fracture	Conchoidal - step like
Mohs Scale hardness	10[1]
Luster	Adamantine[1]
Polish luster	Adamantine[1]
Refractive index	2. In Mineralogy, shape and size give rise to descriptive terms applied to the typical appearance or habit of Crystals The many terms used by mineralogists An octahedron (plural octahedra is a Polyhedron with eight faces A crystal system is a category of Space groups which characterize Symmetry of structures in three dimensions with Translational symmetry in three directions Cleavage, in Mineralogy, is the tendency of crystalline materials to split along definite planes creating smooth surfaces of which there are several named types In the field of Mineralogy, fracture is a term used to describe the shape and texture of the surface formed when a Mineral is broken Conchoidal Fracture describes the way that Brittle materials break when they do not follow any natural planes of separation. The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium 4175–2. 4178
Optical Properties	Singly Refractive[1]
Birefringence	none[1]
Dispersion	. Birefringence, or double refraction, is the decomposition of a ray of Light into two rays (the ordinary ray and the extraordinary ray In Optics, dispersion is the phenomenon in which the Phase velocity of a wave depends on its frequency 044[1]
Pleochroism	none[1]
Ultraviolet fluorescence	colorless to yellowish stones - inert to strong in long wave, and typically blue. Pleochroism is an Optical phenomenon in which grains of a rock appear to be different colors when observed at different angles under a Petrographic microscope. Fluorescence is a Luminescence that is mostly found as an Weaker in short wave. [1]
Absorption spectra	In pale yellow stones a 415. Absorption spectroscopy refers to a range of techniques employing the interaction of electromagnetic radiation with matter 5 nm line is typical. Irradiated and annealed diamonds often show a line around 594 nm when cooled to low temperatures. [1]
Streak	White
Specific gravity	3. The streak (also called powder color) of a Mineral is the Color of the powder produced when it is dragged across an unweathered surface Specific gravity is defined as the ratio of the Density of a given solid or liquid substance to the density of water at a specific temperature and pressure typically 52 (+/- . 01)[1]
Density	3. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 5-3. 53 g/cm³
Diaphaneity	Transparent to subtransparent to translucent

In mineralogy, diamond is the allotrope of carbon where the carbon atoms are arranged in an isometric-hexoctahedral crystal lattice. Mineralogy is an Earth Science focused around the Chemistry, Crystal structure, and physical (including optical) properties of Minerals This is a list of the Allotropes of Carbon. Diamond See also Diamond Diamond is one of the best known allotropes Its hardness and high dispersion of light make it useful for industrial applications and jewelry. In Optics, dispersion is the phenomenon in which the Phase velocity of a wave depends on its frequency Light, or visible light, is Electromagnetic radiation of a Wavelength that is visible to the Human eye (about 400–700 Jewellery (also spelled jewelry, see spelling differences) is a personal Ornament, such as a necklace ring or bracelet made from Gemstones It is the hardest known naturally-occuring mineral. Hardness refers to various properties of Matter in the Solid phase that give it high resistance to various kinds of shape change when Force A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific It is possible to treat regular diamonds under a combination of high pressure and high temperature to produce diamonds (known as Type-II diamonds) that are harder than the diamonds used in hardness gauges. ^[2] Presently, only aggregated diamond nanorods, a material created using ultrahard fullerite (C₆₀) is confirmed to be harder, although other substances such as cubic boron nitride, rhenium diboride and ultrahard fullerite itself are comparable. Aggregated diamond nanorods, or ADNR s (also called "hyperdiamond" are an allotrope of Carbon believed to be the hardest and least "C60" and "C-60" redirect here For other uses see C60 (disambiguation. Boron nitride ( BN) is a binary chemical compound, consisting of equal numbers of Boron and Nitrogen atoms Rhenium diboride ( Re[[Boron B]]2 is a synthetic Superhard material. "C60" and "C-60" redirect here For other uses see C60 (disambiguation.

Diamonds are specifically renowned as a material with superlative physical qualities; they make excellent abrasives because they can be scratched only by other diamonds, borazon, ultrahard fullerite, rhenium diboride, or aggregated diamond nanorods, which also means they hold a polish extremely well and retain their lustre. An abrasive is a material often a Mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away Borazon, a Boron nitride Allotrope, is the fourth hardest substance after Aggregated diamond nanorods, Ultrahard fullerite, and Diamond In Nanotechnology, nanorods are one morphology of nanoscale objects Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. Approximately 130 million carats (26,000 kg) are mined annually, with a total value of nearly USD $9 billion, and about 100,000 kg (220,000 lb) are synthesized annually. The carat is a unit of Mass used for measuring gems and Pearls Currently a carat is defined as exactly 200  mg (0 The United States dollar ( sign: $; code: USD) is the unit of Currency of the United States; it has also been ^[3]

The name diamond derives from the ancient Greek ἀδάμας (adamas) "invincible", "untamed", from ἀ- (a-), "un-" + δαμάω (damáo), "to overpower, to tame". Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly They have been treasured as gemstones since their use as religious icons in ancient India and usage in engraving tools also dates to early human history. A gemstone or gem, also called a precious or semi-precious stone, is a piece of attractive Mineral, which &mdash when cut and polished &mdash An icon (from Greek εἰκών eikōn, "image" is a religious work of art most commonly a painting from Eastern Christianity. This article is about the kingdoms as reflected in Sanskrit literature Engraving is the practice of incising a design onto a hard usually flat surface by cutting grooves into it Prehistory See also Prehistory Paleolithic See also Paleolithic, Recent African Origin, Early Homo sapiens ^[4][5] Popularity of diamonds has risen since the 19th century because of increased supply, improved cutting and polishing techniques, growth in the world economy, and innovative and successful advertising campaigns. They are commonly judged by the “four Cs”: carat, clarity, color, and cut.

Roughly 49% of diamonds originate from central and southern Africa, although significant sources of the mineral have been discovered in Canada, India, Russia, Brazil, and Australia. Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld For a topic outline on this subject see List of basic Australia topics. They are mined from kimberlite and lamproite volcanic pipes, which can bring diamond crystals, originating from deep within the Earth where high pressures and temperatures enable them to form, to the surface. Kimberlite is a type of potassic Volcanic rock best known for sometimes containing Diamonds It is named after the town of Kimberley in South Africa Lamproites are ultrapotassic mantle -derived volcanic rocks. They have low CaO Al2O3 Na2O high K2O/Al2O3 Volcanic pipes are subterranean geological structures formed by the violent Supersonic eruption of deep-origin Volcanoes They are considered The mining and distribution of natural diamonds are subjects of frequent controversy such as with concerns over the sale of conflict diamonds (aka blood diamonds) by African paramilitary groups. In relation to diamond trading blood diamond (also called a converted diamond, conflict diamond, hot diamond or a war diamond) refers to a diamond A paramilitary is a force whose function and organization are similar to those of a professional military force but which are not regarded as having the same status

Material properties

Main article: Material properties of diamond

See also: Crystallographic defects in diamond

Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in structure. Diamond is transparent to opaque optically isotropic, 3D - Crystalline Carbon. Crystallographic defects in the Crystal lattice of Diamond are common they may be the result of extrinsic substitutional impurities, or intrinsic (interstitial

A diamond is a transparent crystal of tetrahedrally bonded carbon atoms and crystallizes into the face centered cubic diamond lattice structure. In Optics, transparency (also called pellucidity) is the Material property of allowing In Materials science, a crystal is a Solid in which the constituent Atoms Molecules or Ions are packed in a regularly ordered repeating Images See also Cubic honeycomb The cubic crystal system (or isometric) is a Crystal system where the Unit cell is in the shape of a Cube. The diamond cubic Crystal structure is a repeating pattern that atoms may adopt as certain Materials solidify Diamonds have been adapted for many uses because of the material's exceptional physical characteristics. Most notable are its extreme hardness, its high dispersion index, and extremely high thermal conductivity (900 – 2320 W/m K). In Optics, dispersion is the phenomenon in which the Phase velocity of a wave depends on its frequency In Physics, thermal conductivity, k is the property of a material that indicates its ability to conduct Heat. Above 1700 °C (1973 K / 3583 °F), diamond is converted to graphite^[6]. The Mineral graphite, as with Diamond and Fullerene, is one of the Allotropes of carbon. Naturally occurring diamonds have a density ranging from 3. 15 to 3. 53 g/cm³, with very pure diamond typically extremely close to 3. 52 g/cm³.

Hardness

Diamond is the hardest natural material known; hardness is defined as resistance to scratching. ^[7] Diamond has a hardness of 10 (hardest) on Mohs scale of mineral hardness. The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material ^[8] Diamond's hardness has been known since antiquity, and is the source of its name.

The hardest diamonds in the world are from the New England area in New South Wales, Australia. New England is the name given to a region in the north of the state of New South Wales, Australia. For a topic outline on this subject see List of basic Australia topics. These diamonds are generally small, perfect to semiperfect octahedra, and are used to polish other diamonds. Their hardness is considered to be a product of the crystal growth form, which is single stage growth crystal. Crystal growth is a major stage of a crystallization process, after the Nucleation stage Most other diamonds show more evidence of multiple growth stages, which produce inclusions, flaws, and defect planes in the crystal lattice, all of which affect their hardness. ^[9]

The hardness of diamonds contributes to its suitability as a gemstone. A gemstone or gem, also called a precious or semi-precious stone, is a piece of attractive Mineral, which &mdash when cut and polished &mdash Because it can only be scratched by other diamonds, it maintains its polish extremely well. Unlike many other gems, it is well-suited to daily wear because of its resistance to scratching—perhaps contributing to its popularity as the preferred gem in an engagement or wedding rings, which are often worn every day. In Western tradition an engagement ring is a ring worn by a woman indicating her Engagement to be married. A wedding ring or wedding band consists of a Metal ring, often set with diamonds or other precious stones

Industrial use of diamonds has historically been associated with their hardness; this property makes diamond the ideal material for cutting and grinding tools. As the hardest known naturally-occurring material, diamond can be used to polish, cut, or wear away any material, including other diamonds. However, diamond is a poor choice for machining ferrous alloys at high speeds. At the high temperatures created by high speed machining, carbon is soluble in iron, leading to greatly increased wear on diamond tools as compared to other alternatives. Common industrial adaptations of this ability include diamond-tipped drill bits and saws, or use of diamond powder as an abrasive. For the ficitonal character see Drill Bit (Transformers. Drill bits are cutting tools used to create cylindrical holes An abrasive is a material often a Mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away Industrial-grade diamonds are either unsuitable for use as gems or synthetically produced, which lowers their value and makes their use economically feasible.

Electrical conductivity

Other specialized applications also exist or are being developed, including use as semiconductors: some blue diamonds are natural semiconductors, in contrast to most other diamonds, which are excellent electrical insulators. A semiconductor' is a Solid material that has Electrical conductivity in between a conductor and an insulator; it can vary over that An insulator, also called a Dielectric, is a material that resists the flow of Electric current. ^[8] However, substantial conductivity has been observed for undoped diamond when exposed to air. ^[10]

Toughness

Toughness relates to a material's ability to resist breakage from forceful impact. The toughness of natural diamond has been measured as 3. Toughness, in Materials science and Metallurgy, is the resistance to Fracture of a material when stressed. 4 MN m^-3/2,^[11] which is good compared to other gemstones, but poor compared to most engineering materials. As with any material, the macroscopic geometry of a diamond contributes to its resistance to breakage. Diamond is therefore more fragile in some orientations than others.

Color

Main article: Diamond color

Diamond color can occur in blue, green, black, translucent white, pink, violet, orange, purple and red, though yellow and brown are by far the most common colors. A chemically pure and structurally perfect diamond is perfectly transparent with no Hue, or color. ^[8] "Black" diamonds are not truly black, but rather contain numerous dark inclusions that give the gems their dark appearance. Colored diamonds contain impurities or structural defects that cause the coloration, while pure or nearly pure diamonds are transparent and colorless. Most diamond impurities replace a carbon atom in the crystal lattice, known as a carbon flaw. In Mineralogy and Crystallography, a crystal structure is a unique arrangement of Atoms in a Crystal. A carbon flaw is a blemish present within a Diamond crystalline form of carbon usually seen as a black spot The most common impurity, nitrogen, causes a slight to intense yellow coloration depending upon the type and concentration of nitrogen present. Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 ^[8] The Gemological Institute of America (GIA) classifies low saturation yellow and brown diamonds as diamonds in the normal color range, and applies a grading scale from 'D' (colorless) to 'Z' (light yellow). The Gemological Institute of America, or GIA, is a non-profit institute dedicated to research and education in the field of Gemology.

In October 2007 a blue diamond fetched nearly $8 million. The blue hue was a result of trace amounts of boron in the stone's crystal structure. ^[12]

Identification

Diamonds can be identified by their high thermal conductivity. Their high refractive index is also indicative, but other materials have similar refractivity. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium Diamonds do cut glass, but other materials above glass on Mohs scale such as quartz do also. The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material Diamonds easily scratch other diamonds, but this damages both diamonds. ^[13]

Natural history

Formation

The formation of natural diamond requires very specific conditions. Diamond formation requires exposure of carbon-bearing materials to high pressure, ranging approximately between 45 and 60 kilobars,^[14] but at a comparatively low temperature range between approximately 1652–2372 °F (900–1300 °C). Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface Citations The bar (symbol bar) decibar (symbol dbar) and the millibar (symbol mbar, also mb are units of Pressure. Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature ^[14] These conditions are known to be met in two places on Earth; in the lithospheric mantle below relatively stable continental plates, and at the site of a meteorite strike. The lithosphere (IPA, from the Greek λίθος for "rocky" + σφαίρα for "sphere" is the solid outermost shell of a rocky Planet. Plate tectonics (from Greek τέκτων tektōn "builder" or "mason" describes the large scale motions of Earth 's Lithosphere A meteorite is a natural object originating in Outer space that survives an impact with the Earth 's surface

Diamonds formed in cratons

The conditions for diamond formation to happen in the lithospheric mantle occur at considerable depth corresponding to the aforementioned requirements of temperature and pressure. These depths are estimated to be in between 140–190 kilometers (90–120 miles)^[14][8] though occasionally diamonds have crystallized at depths of 300-400 km (180-250 miles) as well. ^[15] The rate at which temperature changes with increasing depth into the Earth varies greatly in different parts of the Earth. The geothermal gradient is the rate of increase in temperature per unit depth in the Earth. In particular, under oceanic plates the temperature rises more quickly with depth, beyond the range required for diamond formation at the depth required. ^[14] The correct combination of temperature and pressure is only found in the thick, ancient, and stable parts of continental plates where regions of lithosphere known as cratons exist. Plate tectonics (from Greek τέκτων tektōn "builder" or "mason" describes the large scale motions of Earth 's Lithosphere A craton ( Greek kratos / κρἀτος ( neut. "strength" is an old and stable part of the Continental crust that has survived ^[14] Long residence in the cratonic lithosphere allows diamond crystals to grow larger.

The slightly misshapen octahedral shape of this rough diamond crystal in matrix is typical of the mineral. Its lustrous faces also indicate that this crystal is from a primary deposit.

Through studies of carbon isotope ratios (similar to the methodology used in carbon dating, except with the stable isotopes C-12 and C-13), it has been shown that the carbon found in diamonds comes from both inorganic and organic sources. Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides Radiocarbon dating is a Radiometric dating method that uses the naturally occurring Radioisotope Carbon-14 (14C to determine the age of Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge Some diamonds, known as harzburgitic, are formed from inorganic carbon originally found deep in the Earth's mantle. A peridotite is a dense coarse-grained Igneous rock, consisting mostly of the minerals Olivine and Pyroxene. The mantle is a part of an Astronomical object. The interior of the Earth, similar to the other Terrestrial planets, is Chemically divided In contrast, eclogitic diamonds contain organic carbon from organic detritus that has been pushed down from the surface of the Earth's crust through subduction (see plate tectonics) before transforming into diamond. Eclogite (ˈɛklədʒaɪt is a coarse-grained Mafic ( Basaltic in composition Metamorphic rock. In Biology, detritus is non-living particulate organic material (as opposed to dissolved organic material In Geology, a crust is the outermost solid shell of a planet or moon In Geology, a subduction zone is an area on Earth where two tectonic plates meet and move towards one another with one sliding underneath the other Plate tectonics (from Greek τέκτων tektōn "builder" or "mason" describes the large scale motions of Earth 's Lithosphere ^[8] These two different source carbons have measurably different ¹³C:¹²C ratios. Diamonds that have come to the Earth's surface are generally very old, ranging from under 1 billion to 3. 3 billion years old.

Diamonds occur most often as euhedral or rounded octahedra and twinned octahedra known as macles or maccles. Euhedral Crystals are those that are well-formed with sharp easily-recognized faces An octahedron (plural octahedra is a Polyhedron with eight faces Crystal twinning occurs when two separate crystals share some of the same Crystal lattice points in a symmetrical manner As diamond's crystal structure has a cubic arrangement of the atoms, they have many facets that belong to a cube, octahedron, rhombicosidodecahedron, tetrakis hexahedron or disdyakis dodecahedron. Facets are flat faces on geometric shapes The organization of naturally occurring facets was key to early developments in Crystallography, since they reflect the underlying A cube is a three-dimensional solid object bounded by six square faces facets or sides with three meeting at each vertex. An octahedron (plural octahedra is a Polyhedron with eight faces The rhombicosidodecahedron, or small rhombicosidodecahedron, is an Archimedean solid. A tetrakis hexahedron is an Archimedean dual solid or a Catalan solid. See also Disdyakis triacontahedron Bisected hexagonal tiling The crystals can have rounded off and unexpressive edges and can be elongated. Sometimes they are found grown together or form double "twinned" crystals grown together at the surfaces of the octahedron. These different shapes and habits of the diamonds result from differing external circumstances. Diamonds (especially those with rounded crystal faces) are commonly found coated in nyf, an opaque gum-like skin. ^[16]

Diamonds and meteorite impact craters

Diamonds can also form in other natural high-pressure events. Very small diamonds, known as microdiamonds or nanodiamonds, have been found in meteorite impact craters. A meteorite is a natural object originating in Outer space that survives an impact with the Earth 's surface In the broadest sense the term impact crater can be applied to any depression natural or manmade resulting from the high velocity impact of a projectile with larger body Such impact events create shock zones of high pressure and temperature suitable for diamond formation. See also Impact crater An impact event is the Collision of a large Meteoroid, Asteroid or Comet (generically Impact-type microdiamonds can be used as one indicator of ancient impact craters. ^[8]

Extraterrestrial diamonds

Not all diamonds found on earth originated here. A type of diamond called carbonado diamond that is found in South America and Africa was deposited there via an asteroid impact (not formed from the impact) about 3 billion years ago. Carbonado commonly known as the 'Black Diamond' is a natural Polycrystalline Diamond found in alluvial deposits in the Central African Republic South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a ^[17][18] These diamonds formed in the intrastellar environment.

Presolar grains in many meteorites found on earth contain nanodiamonds of extraterrestrial origin, probably formed in supernovas. Presolar grains are isotopically-distinct clusters of material found in the fine-grained matrix of primitive Meteorites, whose differences from the surrounding meteorite A supernova (plural supernovae or supernovas) is a stellar Explosion.

Some White dwarf stars are believed to have a carbon core. A white dwarf, also called a degenerate dwarf, is a small Star composed mostly of Electron-degenerate matter. A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth The largest diamond found in the universe, so far, is located 50 light years away in the constellation Centaurus. The Harvard Smithsonian Center for Astrophysics believes the 2,500 mile-wide diamond was once the heart of a star. It is estimated to be ten billion trillion trillion carats, more or less. It was named Lucy, in honor of the Beatle's song "Lucy in the Sky With Diamonds". ^[19][2]

Surfacing

Schematic diagram of a volcanic pipe

Diamond-bearing rock is brought close to the surface through deep-origin volcanic eruptions. Plate tectonics and hotspots Divergent plate boundaries At the The magma for such a volcano must originate at a depth where diamonds can be formed,^[8] 150 km (90 miles) deep or more (three times or more the depth of source magma for most volcanoes); this is a relatively rare occurrence. Magma (Plurals magmas and magmata) is molten rock that sometimes forms beneath the surface of the Earth (or any other Terrestrial planet These typically small surface volcanic craters extend downward in formations known as volcanic pipes. Volcanic pipes are subterranean geological structures formed by the violent Supersonic eruption of deep-origin Volcanoes They are considered ^[8] The pipes contain material that was transported toward the surface by volcanic action, but was not ejected before the volcanic activity ceased. During eruption these pipes are open to the surface, resulting in open circulation; many xenoliths of surface rock and even wood and/or fossils are found in volcanic pipes. This article concerns the geologic term for other uses see Xenolith (disambiguation A xenolith ( Greek: 'foreign rock' is a rock FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. Diamond-bearing volcanic pipes are closely related to the oldest, coolest regions of continental crust (cratons). The continental crust is the layer of granitic, Sedimentary, and Metamorphic rocks which form the Continents and the areas of shallow seabed A craton ( Greek kratos / κρἀτος ( neut. "strength" is an old and stable part of the Continental crust that has survived This is because cratons are very thick, and their lithospheric mantle extends to great enough depth that diamonds are stable. The lithosphere (IPA, from the Greek λίθος for "rocky" + σφαίρα for "sphere" is the solid outermost shell of a rocky Planet. Not all pipes contain diamonds, and even fewer contain enough diamonds to make mining economically viable.

The magma in volcanic pipes is usually one of two characteristic types, which cool into igneous rock known as either kimberlite or lamproite. Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock Kimberlite is a type of potassic Volcanic rock best known for sometimes containing Diamonds It is named after the town of Kimberley in South Africa Lamproites are ultrapotassic mantle -derived volcanic rocks. They have low CaO Al2O3 Na2O high K2O/Al2O3 ^[8] The magma itself does not contain diamond; instead, it acts as an elevator that carries deep-formed rocks (xenoliths), minerals (xenocrysts), and fluids upward. This article concerns the geologic term for other uses see Xenolith (disambiguation A xenolith ( Greek: 'foreign rock' is a rock These rocks are characteristically rich in magnesium-bearing olivine, pyroxene, and amphibole minerals^[8] which are often altered to serpentine by heat and fluids during and after eruption. Magnesium (mægˈniːziəm is a Chemical element with the symbol Mg, Atomic number 12 Atomic weight 24 The Mineral olivine (when gem-quality also called Peridot) is a Magnesium Iron silicate with the formula ( Mg The pyroxenes are a group of important rock-forming Silicate minerals found in many Igneous and metamorphic rocks. Amphibole (pronounced amfi-bowl defines an important group of generally dark-colored rock-forming inosilicate Minerals composed of double chain SiO4 The serpentine group describes a group of common rock-forming hydrous Magnesium Iron phyllosilicate (()3 Minerals they Certain indicator minerals typically occur within diamondiferous kimberlites and are used as mineralogic tracers by prospectors, who follow the indicator trail back to the volcanic pipe which may contain diamonds. These minerals are rich in chromium (Cr) or titanium (Ti), elements which impart bright colors to the minerals. Chromium (ˈkroʊmiəm is a Chemical element which has the symbol Cr and Atomic number 24 Titanium (taɪˈteɪniəm is a Chemical element with the symbol Ti and Atomic number 22 The most common indicator minerals are chromian garnets (usually bright red Cr-pyrope, and occasionally green ugrandite-series garnets), eclogitic garnets, orange Ti-pyrope, red high-Cr spinels, dark chromite, bright green Cr-diopside, glassy green olivine, black picroilmenite, and magnetite. The garnet group includes a group of minerals that have been used since the Bronze Age as gemstones and abrasives This article is about the mineral For the bird sometimes placed in the monotypic genus Pyrope see Fire-eyed Diucon. The spinels are any of a class of Minerals of general formulation XY2 O 4 which Crystallize in the cubic (isometric Chromite is iron magnesium chromium oxide (Fe MgCr2O4 It is an Oxide Mineral belonging to the Spinel group Diopside is a Monoclinic Pyroxene Mineral with composition MgCaSi2O6 The Mineral olivine (when gem-quality also called Peridot) is a Magnesium Iron silicate with the formula ( Mg Ilmenite is a weakly magnetic titanium-iron oxide Mineral which is iron-black or steel-gray Magnetite is not to be confused with Magnesite or Maghemite. Magnetite is a ferrimagnetic Mineral with chemical ^[8] Kimberlite deposits are known as blue ground for the deeper serpentinized part of the deposits, or as yellow ground for the near surface smectite clay and carbonate weathered and oxidized portion. Clay minerals are hydrous Aluminium phyllosilicates, sometimes with variable amounts of Iron, Magnesium, Alkali metals Alkaline Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and Weathering is the decomposition of earth rocks, Soils and their Minerals through direct contact with the planet's Atmosphere. Redox (shorthand for reduction-oxidation reaction describes all Chemical reactions in which atoms have their Oxidation number ( Oxidation state

Once diamonds have been transported to the surface by magma in a volcanic pipe, they may erode out and be distributed over a large area. Erosion is the carrying away or displacement of solids ( Sediment, Soil, rock and other particles usually by the agents of currents such as wind A volcanic pipe containing diamonds is known as a primary source of diamonds. Secondary sources of diamonds include all areas where a significant number of diamonds, eroded out of their kimberlite or lamproite matrix, accumulate because of water or wind action. These include alluvial deposits and deposits along existing and ancient shorelines, where loose diamonds tend to accumulate because of their approximate size and density. Alluvium (from the Latin, alluvius, from alluere, "to wash against" is Soil or Sediments deposited by a river or other running Diamonds have also rarely been found in deposits left behind by glaciers (notably in Wisconsin and Indiana); however, in contrast to alluvial deposits, glacial deposits are not known to be of significant concentration and are therefore not viable commercial sources of diamond. Wisconsin ( or wɪˈskɑnsɨn (French Ouisconsin) is one of the fifty United States of America, located in the north central part of the United States The State of Indiana ( was the 19th US state admitted into the union Alluvium (from the Latin, alluvius, from alluere, "to wash against" is Soil or Sediments deposited by a river or other running

History and gemological characteristics

Main article: Diamond (gemstone)

Diamonds are thought to have been first recognized and mined in India (Golconda being one of them), where significant alluvial deposits of the stone could then be found along the rivers Penner, Krishna and Godavari. The diamond is one of the most well-known and sought-after Gemstones Diamonds have been known to mankind and used as decorative items since ancient times some of the earliest India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country Golkonda (or Golconda) Telugu గోల్కొండ, a ruined city of south-central India is situated west of Hyderabad, capital of ancient Hyderabad Diamonds have been known in India for at least 3000 years but most likely 6000 years. ^[20] In 1813, Humphry Davy used a lens to concentrate the rays of the sun on a diamond in an atmosphere of oxygen, and showed that the only product of the combustion was carbon dioxide, proving that diamond is composed of carbon. Sir Humphry Davy 1st Baronet FRS MRIA (17 December 1778 &ndash 29 May 1829 was a British Chemist and inventor Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single ^[21] Later, he showed that in an atmosphere devoid of oxygen, diamond is converted to graphite. The Mineral graphite, as with Diamond and Fullerene, is one of the Allotropes of carbon. The most familiar usage of diamonds today is as gemstones used for adornment a usage which dates back into antiquity. NOTICE TO WOULD-BE-ROMEOS*************** The dispersion of white light into spectral colors, is the primary gemological characteristic of gem diamonds. A spectral color is a color that is evoked by a single Wavelength of Light in the Visible spectrum, or by a relatively narrow band of wavelengths In the twentieth century, experts in the field of gemology have developed methods of grading diamonds and other gemstones based on the characteristics most important to their value as a gem. Gemology ( gemmology outside the United States) is the Science, Art and Profession of identifying and evaluating Gemstones Four characteristics, known informally as the four Cs, are now commonly used as the basic descriptors of diamonds: these are carat, cut, color, and clarity.

The diamond industry

See also: Diamonds as an investment

A round brilliant cut diamond set in a ring

The diamond industry can be broadly separated into two basically distinct categories: one dealing with gem-grade diamonds and another for industrial-grade diamonds. For chemical optical and physical properties and applications of diamonds see Diamond. A brilliant is a diamond or other Gemstone, cut in a particular form with numerous facets so as to have especial brilliancy While a large trade in both types of diamonds exists, the two markets act in dramatically different ways.

Gem diamond industry

Main article: Diamond (gemstone)

A large trade in gem-grade diamonds exists. The diamond is one of the most well-known and sought-after Gemstones Diamonds have been known to mankind and used as decorative items since ancient times some of the earliest A gemstone or gem, also called a precious or semi-precious stone, is a piece of attractive Mineral, which &mdash when cut and polished &mdash Unlike precious metals such as gold or platinum, gem diamonds do not trade as a commodity: there is a substantial mark-up in the sale of diamonds, and there is not a very active market for resale of diamonds. Precious Metal is the eighteenth episode in the of the popular American Crime drama, which is set in Las Vegas, Nevada. Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 Platinum (ˈplætɪnəm is a Chemical element with the Atomic symbol Pt and an Atomic number of 78 A commodity is anything for which there is demand but which is supplied without qualitative differentiation across a market One hallmark of the trade in gem-quality diamonds is its remarkable concentration: wholesale trade and diamond cutting is limited to a few locations. Diamond cutting is the art skill and increasingly science of changing a diamond from a rough stone into a Faceted gem 92% of diamond pieces cut in 2003 were in Surat, Gujarat, India. Gujarat (ગુજરાત Gujǎrāt, pronounced) is a state in western India. [1] Other important centers of diamond cutting and trading are Antwerp, London, New York, Tel Aviv, Amsterdam. ||-||-||-||} Antwerp ( Dutch:, French: Anvers) is a City and Municipality in Belgium and the capital of the London ( ˈlʌndən is the capital and largest urban area in the United Kingdom. The City of New York Tel Aviv-Yafo (תֵּל ־אָבִיב-יָפוֹ تل أبيب Tal ʾAbīb) (usually Tel Aviv) is the second-largest city in Israel Amsterdam (pronounced) is the capital and largest city of the Netherlands, located in the province of North Holland in the west A single company—De Beers—controls a significant proportion of the trade in diamonds. De Beers and the various companies within the De Beers Family of Companies engage in exploration for diamonds, diamond mining diamond trading and industrial diamond manufacture They are based in Johannesburg, South Africa and London, England. Johannesburg ( Pronounced /jō-hān'ĭs-bûrg'/ is the largest city in South Africa. The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa London ( ˈlʌndən is the capital and largest urban area in the United Kingdom. England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland

The production and distribution of diamonds is largely consolidated in the hands of a few key players, and concentrated in traditional diamond trading centers. The most important being Antwerp, where 80% of all rough diamonds, 50% of all cut diamonds and more than 50% of all rough, cut and industrial diamonds combined are handled. ||-||-||-||} Antwerp ( Dutch:, French: Anvers) is a City and Municipality in Belgium and the capital of the This makes Antwerp the de facto 'world diamond capital'. New York, however, along with the rest of the United States, is where almost 80% of the world's diamonds are sold, including auction sales. New York ( is a state in the Mid-Atlantic and Northeastern regions of the United States and is the nation's third most populous Also, the largest and most unusually shaped rough diamonds end up in New York. The De Beers company, as the world's largest diamond miner holds a clearly dominant position in the industry, and has done so since soon after its founding in 1888 by the British imperialist Cecil Rhodes. Cecil John Rhodes, PC DCL (5 July 1853 &ndash 26 March 1902 was an English -born Businessman mining Magnate, and Politician De Beers owns or controls a significant portion of the world's rough diamond production facilities (mines) and distribution channels for gem-quality diamonds. Mining is the extraction of valuable Minerals or other geological materials from the earth usually (but not always from an Ore body Distribution (or place) is one of the four elements of Marketing mix. The company and its subsidiaries own mines that produce some 40 percent of annual world diamond production. At one time it was thought over 80 percent of the world's rough diamonds passed through the Diamond Trading Company (DTC, a subsidiary of De Beers) in London, but presently the figure is estimated at less than 50 percent. The Diamond Trading Company (DTC is the rough diamond sales and distribution arm of the De Beers Family of Companies

The De Beers diamond advertising campaign is acknowledged as one of the most successful and innovative campaigns in history. De Beers and the various companies within the De Beers Family of Companies engage in exploration for diamonds, diamond mining diamond trading and industrial diamond manufacture N. W. Ayer & Son, the advertising firm retained by De Beers in the mid-20th century, succeeded in reviving the American diamond market and opened up new markets, even in countries where no diamond tradition had existed before. N W Ayer & Son was the first advertising agency in the United States, founded in Philadelphia Pennsylvania in 1869 N. W. Ayer's multifaceted marketing campaign included product placement, advertising the diamond itself rather than the De Beers brand, and building associations with celebrities and royalty. Product placement, or embedded marketing, is a type of Advertising, in which promotional Advertisements placed by marketers using This coordinated campaign has lasted decades and continues today; it is perhaps best captured by the slogan "a diamond is forever". A slogan is a memorable Motto or Phrase used in a Political, commercial, Religious and other context as a repetitive expression of

Further down the supply chain, members of The World Federation of Diamond Bourses (WFDB) act as a medium for wholesale diamond exchange, trading both polished and rough diamonds. A supply chain or logistics network is the system of organizations people technology activities information and resources involved in moving a product or service from World Federation of Diamond Bourses, founded in 1947 was created to unite and to provide bourses trading in rough and polished Diamonds and Precious stones The WFDB consists of independent diamond bourses in major cutting centres such as Tel Aviv, Antwerp, Johannesburg and other cities across the USA, Europe and Asia.

In 2000, the WFDB and The International Diamond Manufacturers Association established the World Diamond Council to prevent the trading of diamonds used to fund war and inhumane acts. The World Diamond Council (also known during its prototype period as the International Diamond Council) is an organization consisting of representatives from Diamond

WFDB's additional activities also include sponsoring the World Diamond Congress every two years, as well as the establishment of the International Diamond Council (IDC) to oversee diamond grading. World Diamond Congress is made up of representation from the World Federation of Diamond Bourses and the International Diamond Manufacturers Association. The World Diamond Council (also known during its prototype period as the International Diamond Council) is an organization consisting of representatives from Diamond

Industrial diamond industry

The market for industrial-grade diamonds operates much differently from its gem-grade counterpart. Industrial diamonds are valued mostly for their hardness and heat conductivity, making many of the gemological characteristics of diamond, including clarity and color, mostly irrelevant. This helps explain why 80% of mined diamonds (equal to about 100 million carats or 20,000 kg annually), unsuitable for use as gemstones and known as bort, are destined for industrial use. Bort or boart is a term used in the Diamond industry to refer to shards of gem -grade/quality diamonds In addition to mined diamonds, synthetic diamonds found industrial applications almost immediately after their invention in the 1950s; another 3 billion carats (600 metric tons) of synthetic diamond is produced annually for industrial use. Synthetic diamond (also known variously as lab-created, manufactured, lab-grown or cultured diamond) is a term used to describe Diamond This article is about the tonne or metric ton For other tons see Ton.

The dominant industrial use of diamond is in cutting, drilling, grinding, and polishing. Most uses of diamonds in these technologies do not require large diamonds; in fact, most diamonds that are gem-quality except for their small size, can find an industrial use. Diamonds are embedded in drill tips or saw blades, or ground into a powder for use in grinding and polishing applications. Specialized applications include use in laboratories as containment for high pressure experiments (see diamond anvil cell), high-performance bearings, and limited use in specialized windows. Pressure experiments are Experiments performed at Pressures lower or higher than Atmospheric pressure, called low-pressure experiments and A diamond anvil cell (DAC consists of two opposing Diamonds with a sample compressed between the Culets Extreme pressure, which can exceed 1000000 A bearing is a device to permit constrained relative motion between two parts typically rotation or linear movement GlassWindowjpg|thumb|right|190px|A stained glass panel depicting Biblical scenes at a historic church in Scotland]] A window is an opening

With the continuing advances being made in the production of synthetic diamonds, future applications are beginning to become feasible. Garnering much excitement is the possible use of diamond as a semiconductor suitable to build microchips from, or the use of diamond as a heat sink in electronics. A semiconductor' is a Solid material that has Electrical conductivity in between a conductor and an insulator; it can vary over that Microchipsjpg|right|thumb|200px|Microchips ( EPROM memory with a transparent window showing the integrated circuit inside A heat sink (or heatsink) is an environment or object that absorbs and dissipates heat from another object using Thermal contact (either direct or radiant Electronics refers to the flow of charge (moving Electrons through Nonmetal conductors (mainly Semiconductors, whereas electrical

Diamond supply chain

See also: List of diamond mines

The diamond supply chain is controlled by a limited number of powerful businesses, and is also highly concentrated in a small number of locations around the world. "Diamond mine" redirects here For the game from PopCap Games also known as Diamond Mine see Bejeweled.

Mining, sources and production

Only a very small fraction of the diamond ore consists of actual diamonds. The ore is crushed, during which care has to be taken in order to prevent larger diamonds from being destroyed in this process and subsequently the particles are sorted by density. Today, diamonds are located in the diamond-rich density fraction with the help of X-ray fluorescence, after which the final sorting steps are done by hand. X-ray fluorescence (XRF is the emission of characteristic "secondary" (or fluorescent X-rays from a material that has been excited by bombarding with high-energy Before the use of X-rays became commonplace, the separation was done with grease belts; diamonds have a stronger tendency to stick to grease than the other minerals in the ore. X-radiation (composed of X-rays) is a form of Electromagnetic radiation.

Historically diamonds were known to be found only in alluvial deposits in southern India. South India is the area encompassing India 's states of Andhra Pradesh, Karnataka, Kerala and Tamil Nadu as well as the union ^[22] India led the world in diamond production from the time of their discovery in approximately the 9th century BCE^[23][20] to the mid-18th century AD, but the commercial potential of these sources had been exhausted by the late 18th century and at that time India was eclipsed by Brazil where the first non-Indian diamonds were found in 1725. ^[20]

Diamond production of primary deposits (kimberlites and lamproites) only started in the 1870's after the discovery of the Diamond fields in South Africa. Production has increased over time and now an accumulated total of 4. 5 billion carats have been mined since that date. ^[24] Interestingly 20% of that amount has been mined in the last 5 years alone and during the last ten years 9 new mines have started production while 4 more are waiting to be opened soon. Most of these mines are located in Canada, Zimbabwe, Angola, and one in Russia. ^[24]

In the US, diamonds have been found in Arkansas, Colorado, and Montana. The United States of America —commonly referred to as the Arkansas ( is a state located in the southern region of the United States. The State of Colorado ( or chiefly by nonresidents) is a state located in the Rocky Mountain region of the United States of America. Montana ( is a state in the Western United States. One-third of the state in the western part contains numerous mountain ranges (approximately 77 named of the northern ^[25][26] In 2004, a startling discovery of a microscopic diamond in the US^[27] led to the January 2008 bulk-sampling of kimberlite pipes in a remote part of Montana. The United States of America —commonly referred to as the Kimberlite is a type of potassic Volcanic rock best known for sometimes containing Diamonds It is named after the town of Kimberley in South Africa Montana ( is a state in the Western United States. One-third of the state in the western part contains numerous mountain ranges (approximately 77 named of the northern ^[28]

Today, most commercially viable diamond deposits are in Russia, Botswana, Australia and the Democratic Republic of Congo. Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending The Republic of Botswana (Lefatshe la Botswana is a Landlocked nation in Southern Africa. For a topic outline on this subject see List of basic Australia topics. The Democratic Republic of the Congo (République démocratique du Congo often referred to as DR Congo, DRC or RDC, and formerly known or referred to ^[29] In 2005, Russia produced almost one-fifth of the global diamond output, reports the British Geological Survey. The British Geological Survey (BGS is a partly publicly-funded body which aims to advance geoscientific knowledge of the United Kingdom landmass and its Continental Australia boasts the richest diamondiferous pipe with production reaching peak levels of 42 metric tons (41 LT/46 ST) per year in the 1990's. ^[25]

There are also commercial deposits being actively mined in the Northwest Territories of Canada, Siberia (mostly in Yakutia territory, for example Mir pipe and Udachnaya pipe), Brazil, and in Northern and Western Australia. The Northwest Territories (ˌnɔrθˌwɛstˈtɛrɨtɔriz ( NWT or NT; French, les Territoires du Nord-Ouest) is a territory Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page Siberia (Сиби́рь Sibir) is the name given to the vast region constituting almost all of Northern Asia and for the most part currently serving Mir Mine (Кимберлитовая алмазная трубка "Мир" English Kimberlite Diamond pipe "Peace" is an abandoned open Udachnaya pipe (тру́бка Уда́чная literally lucky pipe) is a Diamond deposit in the Daldyn-Alakit Kimberlite field in Sakha For a topic outline on this subject see List of basic Australia topics. Diamond prospectors continue to search the globe for diamond-bearing kimberlite and lamproite pipes. Kimberlite is a type of potassic Volcanic rock best known for sometimes containing Diamonds It is named after the town of Kimberley in South Africa Lamproites are ultrapotassic mantle -derived volcanic rocks. They have low CaO Al2O3 Na2O high K2O/Al2O3

Diamond output in 2005

"Blood" diamonds

Main article: Blood diamond

In some of the more politically unstable central African and west African countries, revolutionary groups have taken control of diamond mines, using proceeds from diamond sales to finance their operations. In relation to diamond trading blood diamond (also called a converted diamond, conflict diamond, hot diamond or a war diamond) refers to a diamond "Diamond mine" redirects here For the game from PopCap Games also known as Diamond Mine see Bejeweled. Diamonds sold through this process are known as conflict diamonds or blood diamonds. Major diamond trading corporations continue to fund and fuel these conflicts by doing business with armed groups. In response to public concerns that their diamond purchases were contributing to war and human rights abuses in central Africa and West Africa, the United Nations, the diamond industry and diamond-trading nations introduced the Kimberley Process in 2002, which is aimed at ensuring that conflict diamonds do not become intermixed with the diamonds not controlled by such rebel groups, by providing documentation and certification of diamond exports from producing countries to ensure that the proceeds of sale are not being used to fund criminal or revolutionary activities. Human rights refers to the "basic Rights and freedoms to which all humans are entitled Central Africa is a core Region of the African Continent often considered to include Burundi, the Central African Republic, Chad West Africa or Western Africa is the Westernmost Region of the African Continent. The United Nations ( UN) is an International organization whose stated aims are to facilitate cooperation in International law, International security The Kimberley Process Certification Scheme, popularly known as KPCS is a process designed to certify the origin of Rough diamonds from sources which are free of conflict Although the Kimberley Process has been moderately successful in limiting the number of conflict diamonds entering the market, conflict diamonds smuggled to market continue to persist to some degree (approx. 2–3% of diamonds traded today are possible conflict diamonds^[30]). According to the 2006 book The Heartless Stone, two major flaws still hinder the effectiveness of the Kimberley Process: the relative ease of smuggling diamonds across African borders and giving phony histories, and the violent nature of diamond mining in nations that are not in a technical state of war and whose diamonds are therefore considered "clean. "^[31]

The Canadian Government has setup a body known as Canadian Diamond Code of Conduct^[32] to help authenticate Canadian diamonds. This is a very stringent tracking system of diamonds and helps protect the 'conflict free' label of Canadian diamonds.

Currently, gem production totals nearly 30 million carats (6,000 kg) of cut and polished stones annually, and over 100 million carats (20,000 kg) of mined diamonds are sold for industrial use each year, as are about 100,000 kg of synthesized diamond.

Distribution

The Diamond Trading Company, or DTC, is a subsidiary of De Beers and markets rough diamonds produced both by De Beers mines and other mines from which it purchases rough diamond production. The Diamond Trading Company (DTC is the rough diamond sales and distribution arm of the De Beers Family of Companies Once purchased by sightholders, diamonds are cut and polished in preparation for sale as gemstones. The cutting and polishing of rough diamonds is a specialized skill that is concentrated in a limited number of locations worldwide. Traditional diamond cutting centers are Antwerp, Amsterdam, Johannesburg, New York, and Tel Aviv. ||-||-||-||} Antwerp ( Dutch:, French: Anvers) is a City and Municipality in Belgium and the capital of the Amsterdam (pronounced) is the capital and largest city of the Netherlands, located in the province of North Holland in the west Johannesburg ( Pronounced /jō-hān'ĭs-bûrg'/ is the largest city in South Africa. The City of New York Tel Aviv-Yafo (תֵּל ־אָבִיב-יָפוֹ تل أبيب Tal ʾAbīb) (usually Tel Aviv) is the second-largest city in Israel Recently, diamond cutting centers have been established in China, India, and Thailand. China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country The Kingdom of Thailand (ˈtaɪlænd ราชอาณาจักรไทย, râːtɕʰa-ʔaːnaːtɕɑ̀k-tʰɑj Cutting centers with lower cost of labor, notably Surat in Gujarat, India, handle a larger number of smaller carat diamonds, while smaller quantities of larger or more valuable diamonds are more likely to be handled in Europe or North America. Gujarat (ગુજરાત Gujǎrāt, pronounced) is a state in western India. The recent expansion of this industry in India, employing low cost labor, has allowed smaller diamonds to be prepared as gems in greater quantities than was previously economically feasible.

Diamonds which have been prepared as gemstones are sold on diamond exchanges called bourses. There are 26 registered diamond bourses. ^[33] This is the final tightly controlled step in the diamond supply chain; wholesalers and even retailers are able to buy relatively small lots of diamonds at the bourses, after which they are prepared for final sale to the consumer. Diamonds can be sold already set in jewelry, or as is increasingly popular, sold unset ("loose"). According to the Rio Tinto Group, in 2002 the diamonds produced and released to the market were valued at US$9 billion as rough diamonds, US$14 billion after being cut and polished, US$28 billion in wholesale diamond jewelry, and retail sales of US$57 billion. Rio Tinto is a multinational Mining and resources group founded originally in 1873 Jewellery (also spelled jewelry, see spelling differences) is a personal Ornament, such as a necklace ring or bracelet made from Gemstones [2]

Crater of Diamonds State Park

The Crater of Diamonds State Park is an Arkansas State Park located near Murfreesboro in Pike County, Arkansas, USA containing the only diamond bearing site in the world that is open to the public. The Crater of Diamonds State Park is an Arkansas State Park located near Murfreesboro in Pike County Arkansas, USA containing the only Pike County is a County located in the US state of Arkansas. As of 2000 the population is 11303

Synthetics, simulants, and enhancements

Main articles: Synthetic diamond, Diamond simulant, and Diamond enhancement

Natural diamonds have formed naturally within the earth. Synthetic diamond (also known variously as lab-created, manufactured, lab-grown or cultured diamond) is a term used to describe Diamond This article addresses the many imitations of diamond For a broader discussion of diamonds see Diamond. Diamond enhancements are specific treatments performed on natural and sometimes Synthetic diamonds (usually those already cut and polished into gems, which are designed Synthetic diamonds are purely manufactured. Synthetic diamond (also known variously as lab-created, manufactured, lab-grown or cultured diamond) is a term used to describe Diamond A diamond simulant is defined as a non-diamond material that is used to simulate the appearance of a diamond. This article addresses the many imitations of diamond For a broader discussion of diamonds see Diamond. Diamond-simulant gems are often referred to as diamante.

The gemological and industrial uses of diamond have created a large demand for rough stones. The demand for industrial diamonds has long been satisfied in large part by synthetic diamonds, which have been manufactured by various processes for more than half a century. Synthetic diamond (also known variously as lab-created, manufactured, lab-grown or cultured diamond) is a term used to describe Diamond However, in recent years it has become possible to produce gem-quality synthetic diamonds of significant size. ^[34]

The majority of commercially available synthetic diamonds are yellow in color and produced by so called High Pressure High Temperature (HPHT) processes. ^[35] The yellow color is caused by nitrogen impurities. Other colors may also be reproduced such as blue, green or pink which are a result of the addition of boron or from irradiation after synthesis. ^[36]

At present the annual production of gem quality synthetic diamonds is only a few thousand carats, whereas the total production of natural diamonds is around 120 million carats. Although the production of colorless synthetic diamonds is dwarfed by that of natural diamonds, one can only find one fancy colored diamond for every 10. 000 colorless ones. Since almost the complete production of synthetic diamonds consists of fancy diamonds, there is a high probability that the larger fancy colored diamonds (over 1. 5 carats) will be synthetic. ^[37]

Today, trained gemologists can generally also distinguish between natural diamonds and synthetic diamonds. Although synthetic and natural diamonds are theoretically identical and indistinguishable from each other, diamonds from each of the two categories usually incorporate their own characteristic imperfections, arising from the circumstances of their creation, that allow them to be distinguished from each other. In the case of synthetic diamonds, for example, depending on the method of production (either high-pressure/high-temperature [HPHT] produced or chemical vapor deposition [CVD] produced) and the color of the diamond (colored, D-Z color range or D-J color range), several methods of identification can be attempted by a gemologist or gemlab: CVD diamonds can usually be identified by an orange fluorescence, D-J colored diamonds can be screened through the Swiss Gemological Organization's (SSEF)^[38] Diamond Spotter, and stones in the D-Z color range can be examined through the DiamondSure UV/visible spectrometer which is a tool developed by De Beers. Chemical vapor deposition (CVD is a Chemical process used to produce high-purity high-performance solid materials ^[39] Similarly, natural diamonds usually have minor imperfections and flaws, such as inclusions of foreign material, that are not seen in synthetic diamonds. The origin of a truly perfect diamond (natural or synthetic) cannot be determined and is largely moot given that perfect diamonds are currently rare from both sources.

A diamond's gem quality, which is not as dependent on material properties as industrial applications, has invited both imitation and the invention of procedures to enhance the gemological properties of natural diamonds. Materials which have similar gemological characteristics to diamond but are not mined or synthetic diamond are known as diamond simulants. The most familiar diamond simulant to most consumers is cubic zirconia (commonly abbreviated as CZ); recently moissanite has also gained popularity and has often been mischaracterized as a diamond simulant, although it is sold and retailed as a replacement for diamond. Cubic zirconia (or CZ) the cubic crystalline form of Zirconium dioxide ( ZrO2) is a Mineral that is widely synthesized Moissanite or Silicon carbide (SiC is a rare mineral that can be found in meteorites and in terrestrial samples Both CZ and moissanite are synthetically produced. However, CZ is a diamond simulant. Diamond enhancements are specific treatments, performed on natural diamonds (usually those already cut and polished into a gem), which are designed to better the gemological characteristics of the stone in one or more ways. These include laser drilling to remove inclusions, application of sealants to fill cracks, treatments to improve a white diamond's color grade, and treatments to give fancy color to a white diamond.

Currently, trained gemologists with appropriate equipment are able to distinguish natural diamonds from simulant diamonds, and they can identify all enhanced natural diamonds. Coatings are more and more used to give a diamond simulant such as cubic zirconia a more "diamond-like" appearance. One such substance, which is heavily advertised, is what scientists refer to as "diamond-like carbon". This is an amorphous carbonaceous material that has some physical properties which are similar to that of the diamond. Advertising suggests (rightfully so or not) that such a coating would transfer some of these diamond-like properties to the coated stone, hence enhancing the diamond simulant. However, modern techniques such as Raman Spectroscopy should easily identify such as treatment. Raman spectroscopy (pronounced S— is a spectroscopic technique used in Condensed matter physics and Chemistry to study vibrational rotational and ^[40]

Producing large synthetic diamonds threatens the business model of the diamond industry, and the ultimate effect of the ready availability of gem-quality diamonds at low cost in the future is hard to predict at this time.

The screening machine use for referring treated or enhanced diamonds as well as synthetics is the DiamondSure, and the definitive analytical machine is the DiamondView produce by the DTC and supplied marketed by the GIA. All of the major diamond testing laboratories world wide are required to have these machines.

See also

• List of famous diamonds
• Diamond cubic
• Diamond drilling

Notes

References

External links

• Video: How a Diamond is Cut and Polished at Eurostar Diamonds International
• Diamond formation phase diagrams and geotherms
• Interactive structure of bulk diamond (Java applet)
• PBS Nature: Diamonds
• Smithsonian's Splendour of Diamonds exhibit
• Historical Diamond Books/References, 5000 pages Most of the books mentioned as references, found online here.