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| :''For alternate meanings, see ]'' | |||
| ] | |||
| The ] '''diamond''' is a ] form of ] (other ] include ] and ]). Diamonds are renowned for their ]—the word "diamond" derives from the Greek ''adamas'' (αδάμας; "impossible to tame")—and their rainbow-like ] of light. These and many other properties make diamond uniquely valuable in ] and ]. | |||
| ==Origins== | |||
| Most diamonds are mined from extinct ]s, where extreme pressure and temperature were suitable for diamond formation. Central and southern ] are the centers of diamond-mining today, although significant deposits have also been discovered in ], ], ], and ]. About 130 million ] (26,000 kg) of diamonds are mined annually, with a total value of nearly $9 billion. In addition, nearly four times that amount (by mass) is artificially produced as ]. | |||
| ==Use in jewelry== | |||
| The ] appeal of diamonds lies in their hardness and optical properties. Diamonds used as gems are cut and polished into a number of faceted shapes in order to accentuate these attractive qualities. The hardness of diamonds allows them to hold a polish extremely well and resist scratching (only other diamonds can scratch a diamond), giving excellent ''luster''. The dispersion of white light into a rainbow of colors, known in the trade as ''fire'', is the other primary characteristic of gem diamonds, and has been highly prized throughout history. Gem diamonds are commonly judged by the '''four Cs''': carat, clarity, color, and cut. Diamonds have been treasured as ]s since at least 2,500 years ago, when they were used in religious ]s in ], but the popularity of diamonds as gemstones increased even more in modern times by new cutting designs. | |||
| ==Use in industry== | |||
| The industrial use of diamonds far exceeds their use as gems. <!-- source: http://www.sciencedaily.com/releases/1999/10/991020080444.htm -->Their industrial use has historically been associated with their hardness; this property makes diamond the ideal material for cutting and grinding tools — common applications include the cutting surfaces of saw blades and drill bits, or use of diamond powder as an ]. Other specialized applications also exist or are being developed, including use as ]s: some blue diamonds are natural semiconductors, in contrast to most other diamonds, which are excellent ]s. Industrial-grade diamonds are either unsuitable for use as gems or synthetically produced, which lowers their price and makes their use economically feasible. Industrial applications, especially as ]s and ] tools, also date to ancient times. | |||
| ==Diamond companies== | |||
| The production and distribution of diamonds is dominated by a handful of companies in traditional mining areas and diamond-trading centers (the most important being ]). The ], based in ], ] and ], ], has been the dominant company in the industry for over one hundred years and owns mines either directly or through subsidiaries that produce some 40 percent of annual world diamond production, while controlling nearly two thirds of the trade in gem diamonds. Some controversy over diamonds has been generated because of the ] practices historically employed by De Beers including strict control of supply and alleged price manipulation, as well as the practice by some African revolutionary groups of selling '']'' in order to fund their often violent activities. | |||
| ==Material properties== | |||
| ] of the diamond crystal.]] | |||
| {{main|Material properties of diamond}} | |||
| Diamond is a ] ] of pure ] consisting of ] bonded carbon atoms. Humans have been able to adapt diamonds for many uses because of the material's exceptional physical characteristics. Most notable among these properties are the extreme ] of diamond and its high ] index. These two properties form the basis for most modern applications of diamond. | |||
| ===Mechanical properties=== | |||
| '''Crystal structure''': Diamonds typically crystallize in the cubic ] and consist of ] bonded carbon atoms. A rare second form called ] has hexagonal symmetry. The tetrahedral arrangement of atoms in a diamond crystal is the source of many of diamond's properties; ], another ] of carbon, has a ] crystal structure and as a result shows dramatically different physical characteristics. | |||
| ] and differentiates it from ].]] | |||
| '''Hardness''': Diamond is the ] known naturally occurring material, scoring 10 on the relative ] and having an ] value of between 167 and 231 ]s in various tests. Diamond's hardness has been known since antiquity, and is the source of its name. | |||
| Broad industrial applications of diamond are based on the extraordinary hardness of diamond. As the hardest known naturally occurring material, diamond can be used to polish, cut, or wear away any material, including other diamonds. Common industrial adaptations of this ability include diamond-tipped drill bits and saws. | |||
| The hardness of diamonds also contributes to its suitability as a ]. Because it can only be scratched by other diamonds, it maintains its polish extremely well, keeping its luster over long periods of time. Unlike many other gems, it is well-suited to daily wear due to its resistance to scratching — perhaps contributing to its popularity as the preferred gem in an ] or ], which are often worn every day. | |||
| '''Toughness''': Unlike hardness, which only denotes resistance to scratching, diamond's ] is only fair to good. Toughness relates to a material's ability to resist breakage from forceful impact. As with any material, the macroscopic geometry of a diamond contributes to its resistance to breakage. Diamonds cut into certain particular shapes are therefore more prone to breakage than others. | |||
| '''Color''': Diamonds occur in a variety of transparent hues — colorless, white, steel, blue, yellow, orange, red, green, pink, brown — or colored black. Diamonds with a detectable hue to them are known as ''colored diamonds''. 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 ]. The most common impurity, ], causes a yellowish or brownish tinge. | |||
| '''Thermodynamic stability''': At surface air pressure (one atmosphere), diamonds are not as stable as graphite, and so the decay of diamond is thermodynamically favorable (δ''H'' = −2 kJ / mol). Diamonds have been shown to burn in the late ], and previously during ] times. So, despite the popular advertising slogan, diamonds are definitely not forever. However, owing to a very large kinetic energy barrier, diamonds are ]; they will not decay into graphite under ]. | |||
| ===Electromagnetic properties=== | |||
| ] | |||
| '''Optical properties''': Diamonds exhibit a high ] of visible light. This strong ability to split white light into its component colors is an important aspect of diamond's attraction as a gemstone, giving it impressive ] action that results in so-called ''fire'' in a well-cut stone. The ] of a diamond, a characterization of how light interacts with the surface of a crystal, is brilliant and is described as ''adamantine'', which simply means diamond-like. Some diamonds exhibit ] of various colors under long wave ], but generally show bluish-white, yellowish or greenish fluorescence under ]. Some diamonds show no fluorescence. | |||
| '''Electrical properties''': Except for most natural blue diamonds which are ]s, diamond is a good electrical ]. Blue diamonds owe their semiconductive property to ] impurities, which act as a ] and cause ] behavior. Natural blue diamonds which are not boron-doped, such as those recently recovered from the ] in ] that owe their color to an overabundance of ] atoms, are not semiconductors. | |||
| '''Thermal properties''': Unlike most electrical insulators, diamond is a good conductor of heat because of the strong covalent bonding within the crystal. Most natural blue diamonds contain ] atoms which replace carbon atoms in the crystal matrix, and also have high thermal conductance. Specially purified synthetic diamond has the highest ] (2000–2500 W/(m·K), five times more than copper) of any known solid at room temperature. Because diamond has such high thermal conductance it is already used in semiconductor manufacture to prevent silicon and other semiconducting materials from overheating. | |||
| ===Media=== | |||
| ] | |||
| {{multi-video start}} | |||
| {{multi-video item | | |||
| filename = Diamond animation.ogg | | |||
| title = Rotating diamond animation | | |||
| description = Animation of a rotating diamond structure (0:12, 3.98 ], ]/] format). | | |||
| format = ] | |||
| }} | |||
| {{multi-video item | | |||
| filename = Diamond stereo animation.ogg | | |||
| title = Rotating stereo animation | | |||
| description = ] of a rotating diamond structure (0:12, 3.74 ], ]/] format). | | |||
| format = ] | |||
| }} | |||
| {{multi-video end}} | |||
| (Java applet). | |||
| ==Natural history== | |||
| ===Formation=== | |||
| Diamond is formed by prolonged exposure of carbon bearing materials to high ] and ]. On ], the formation of diamonds is possible because there are regions deep within the Earth that are at a high enough pressure and temperature that the formation of diamonds is ] favorable (see the diamond ] and ]s ). Under ], diamonds form starting at depths of about 150 kilometers (90 miles), where pressure is roughly 5 ]s and the temperature is around 1200 degrees Celsius (2200 degrees Fahrenheit). Diamond formation under ] takes place at greater depths due to higher temperatures, which require higher pressure for diamond formation. Long periods of exposure to these high pressures and temperatures allow diamond crystals to grow larger. | |||
| ] | |||
| Through studies of carbon ] ratios (similar to the methodology used in ]) except using 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. Some diamonds, known as '']'', are formed from inorganic carbon originally found deep in the Earth's ]. In contrast, '']'' diamonds contain organic carbon from organic ] that has been pushed down from the surface of the Earth's ] through ] (see ]) before transforming into diamond. These two different source carbons have measurably different <sup>13</sup>C:<sup>12</sup>C 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 ] or rounded ] and ] octahedra known as ''macles''. Other forms include ] and cubes. Diamonds (especially those from secondary deposits) are commonly found coated in ''nyf'', an opaque gum-like skin. | |||
| Diamonds can also form in other natural high-pressure high-temperature events. Very small diamonds, known as ''microdiamonds'' or ''nanodiamonds'', have been found in ]s where ]s strike the Earth and create shock zones of high pressure and temperature where diamond formation can occur. Microdiamonds are now used as one indicator of ancient ] impact sites. Especially ancient meteorites may contain "star dust", the remnants of dead stars, some of which is composed of extremely tiny diamond crystals. | |||
| === Surfacing === | |||
| Diamond-bearing rock is forced close to the surface through deep-origin ] eruptions. The ] for such a volcano must originate at a depth where diamonds can be formed, 90 miles (150 km) deep or more (three times or more the depth of source magma for most volcanoes); this is a relatively rare occurrence. Below these typically small volcanoes are formations known as ]s, which contain material that was pushed toward the surface of the earth by volcanic action, but did not erupt before the volcano became ]. Diamond-bearing volcanic pipes are most commonly found in the oldest regions of continental crust, which relates to the fact that these areas are the coolest portions of the earth's crust, and therefore diamonds can form at the shallowest depths. | |||
| The magma in such volcanic pipes is usually one of two characteristic types, which cool into ] known as either ] or ]. The magma itself does not contain diamond; instead, it acts as an elevator that carries deep-formed rocks and material upward. These materials are characteristically rich in certain minerals (usually rich in ]), most notably ]. ], a ] bearing ], typically occurs in kimberlites in association with diamonds and is used as a mineralogic tracer in the search for diamond deposits by prospectors. Kimberlite deposits are known as ''blue ground'', or ''yellow ground'' at the surface where it has been ] and ], based on their appearance. | |||
| Once diamonds have been forced to the surface by magma in a volcanic pipe, they may ] out and be distributed over a large area. 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 due to water or weather action. These include ] deposits and deposits along existing and ancient shorelines, where loose diamonds tend to accumulate due to their approximate size and density. Diamonds have also rarely been found in deposits left behind by ]s (notably in ] and ]); 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. | |||
| Diamonds can also be pushed to the surface through certain processes which may occur when two continental plates collide forcefully, although this phenomenon is less understood and currently assumed to be uncommon. | |||
| ==Gemological characteristics== | |||
| The use of diamonds as gemstones of decorative value is the most familiar use to most people today, and is also the earliest use, with decorative use of diamonds stretching back into antiquity. Over time, especially since around ], experts in the field of ''']''' have developed methods of characterizing diamonds and other gemstones based on the characteristics most important to their value as a gem. Four characteristics, known informally as the '''four Cs''', are now commonly used as the basic descriptors of diamonds: these are ''carat'', ''clarity'', ''color'', and ''cut''. | |||
| Most gem diamonds are traded on the wholesale market based on single values for each of the four Cs; for example knowing that a diamond is rated as 1.5 carats, VS2 clarity, F color, excellent cut, is enough to reasonably establish an expected price range. More detailed information from within each characteristic can then be used to determine actual market value for individual stones. Consumers who purchase individual diamonds are often advised to use the four Cs to pick the diamond that is "right" for them; to these is sometimes added the "fifth C" of ''cost''. | |||
| Other characteristics not described by the four Cs can and do influence the value or appearance of a gem diamond. These characteristics include physical characteristics such as the presence of ], as well as data on a diamond's history including its source and which gemological institute performed evaluation services on the diamond. ''Cleanliness'' also dramatically affects a diamond's beauty. | |||
| === Carat === | |||
| The '''] weight''' (actually mass) of a diamond measures the mass of a diamond. One carat is defined as exactly 200 ]s (about 0.007 ounce). The '''point''' unit — equal to one one-hundredth of a carat (.01 carat, or 2 mg) — is commonly used to denominate the size of diamonds of less than one carat. All else being equal, the value of a diamond increases exponentially in relation to carat size. Larger diamonds are both rarer and more desirable for use as gemstones. A review of comparable diamonds available for purchase in March ] demonstrates this effect (approximate prices for round cut, G color, VS2 diamonds with "1A" cut grade, as listed on http://www.pricescope.com): | |||
| {| border="1" cellpadding="2" cellspacing="0" align="center" | |||
| |- style="background-color: #cccccc;" | |||
| !Carat Size | |||
| !Cost Per Carat (US$) | |||
| !Total Cost (US$) | |||
| |- | |||
| |0.5 carat (50 points) | |||
| |align="right"|3,000 | |||
| |align="right"|1,500 | |||
| |- | |||
| |1.0 carat | |||
| |align="right"|5,000 | |||
| |align="right"|5,000 | |||
| |- | |||
| |1.5 carats | |||
| |align="right"|7,000 | |||
| |align="right"|10,500 | |||
| |- | |||
| |2.0 carats | |||
| |align="right"|10,000 | |||
| |align="right"|20,000 | |||
| |- | |||
| |3.0 carats | |||
| |align="right"|15,000 | |||
| |align="right"|45,000 | |||
| |- | |||
| |5.0 carats | |||
| |align="right"|20,000 | |||
| |align="right"|100,000 | |||
| |} | |||
| The price per carat does not increase smoothly with increasing size. Instead, there are sharp jumps around milestone carat weights, as demand is much higher for diamonds weighing just more than a milestone than for those weighing just less. As an example, a 0.95 carat diamond has a significantly lower price per carat than a comparable 1.05 carat diamond, due to differences in demand. | |||
| In the wholesale trade of gem diamonds, carat is often used in denominating lots of diamonds for sale. For example, a buyer may place an order for 100 carats of 0.5 carat, D–F, VS2-SI1, excellent cut diamonds, indicating he wishes to purchase 200 diamonds (100 carats total mass) of those approximate characteristics. Because of this, diamond prices (particularly among wholesalers and other industry professionals) are often quoted per carat, rather than per stone. | |||
| ''Total carat weight'' (t.c.w.) is a phrase used to describe the total mass of diamonds or other gemstone in a piece of jewelry, when more than one gemstone is used. Diamond earrings, for example, are usually quoted in t.c.w. when placed for sale, indicating the mass of both diamonds together and not each individual diamond. | |||
| ===Clarity=== | |||
| {{main|Diamond clarity}} | |||
| Clarity is a measure of internal defects of a diamond called ''inclusions''. Inclusions may be crystals of a foreign material or another diamond crystal, or structural imperfections such as tiny cracks that can appear whitish or cloudy. The number, size, color, relative location, orientation, and visibility of inclusions can all affect the relative clarity of a diamond. The ] (GIA) and others have developed systems to grade clarity, which are generally based on those inclusions which are visible to a trained professional when a diamond is viewed from above under 10x magnification. | |||
| Diamonds become increasingly rare when considering higher clarity gradings. Only about 20 percent of all diamonds mined have a clarity rating high enough for the diamond to be considered appropriate for use as a gemstone; the other 80 percent are relegated to industrial use. Of that top 20 percent, a significant portion contains an inclusion or inclusions that are visible to the naked eye upon close inspection. Those that do not have a visible inclusion are known as "eye-clean" and are preferred by most buyers, although visible inclusions can sometimes be hidden under the setting in a piece of jewelry. | |||
| Most inclusions present in gem-quality diamonds do not affect the diamonds' performance or structural integrity. However, large clouds can affect a diamond's ability to transmit and scatter light. Large cracks close to or breaking the surface may reduce a diamond's resistance to fracture. | |||
| ===Color=== | |||
| {{main|Diamond color}} | |||
| ] | |||
| A chemically pure and structurally perfect diamond is perfectly transparent with no ], or '''color'''. However, in reality almost no gem-sized natural diamonds are absolutely perfect. The color of a diamond may be affected by chemical impurities and/or structural defects in the ]. Depending on the hue and intensity of a diamond's coloration, a diamond's color can either detract from or enhance its value. For example, most white diamonds are discounted in price as more yellow hue is detectable, while intense pink or blue diamonds (such as the ]) can be dramatically more valuable. | |||
| Most diamonds used as gemstones are basically transparent with little tint, or ''white diamonds''. The most common impurity, ], replaces a small proportion of carbon atoms in a diamond's structure and causes a yellowish to brownish tint. This effect is present in almost all white diamonds; in only the rarest diamonds is the coloration due to this effect undetectable. The GIA has developed a rating system for color in white diamonds, from "D" to "Z" (with D being "colorless" and Z having a clear light yellow or brown coloration), which has been widely adopted in the industry and is universally recognized. Diamonds with higher color grades are rarer, in higher demand, and therefore more expensive, than lower color grades. While the prices are higher for colorless diamonds, the exact color most valued by a consumer is a matter of personal preference, with some preferring the very transparent D–F range, while others prefer the "warmer" colors in the G–J range and still others prefer a clearly visible tint. | |||
| In contrast to yellow or brown hues, diamonds of other colors are much rarer and more valuable. While even a pale pink or blue hue may increase the value of a diamond, more intense coloration is usually considered more desirable and commands the highest prices. A variety of impurities and structural imperfections cause different colors in diamonds, including yellow, pink, blue, red, green, brown, and other hues. Diamonds with unusual or intense coloration are sometimes labeled "fancy" by the diamond industry. Intense yellow coloration is considered one of the fancy colors, and is separate from the color grades of white diamonds. Gemologists have developed rating systems for fancy colored diamonds, but they are not in common use due to the relative rarity of colored diamonds. | |||
| ===Cut=== | |||
| {{main|Diamond cut}} | |||
| The '''cut''' of a diamond describes the manner in which a diamond has been shaped and polished from its beginning form as a rough stone to its final gem proportions. The cut of a diamond describes both the shape a diamond is formed into, as well as the quality of workmanship. ] is the art and science of creating a gem-quality diamond out of mined rough. | |||
| ====Shape==== | |||
| Diamonds do not show all of their beauty as rough stones; instead, they must be cut and polished to exhibit the characteristic fire and brilliance that diamond gemstones are known for. Diamonds are cut into a variety of shapes that are generally designed to accentuate these features. The techniques for shaping diamonds have been developed over hundreds of years, with perhaps the greatest achievements made in ] by ] and gem enthusiast ]. He developed the ] by calculating the ideal shape to return and scatter light when a diamond is viewed from above. The modern round brilliant has 57 facets (polished faces), counting 33 on the ''crown'' (the top half above the middle or ''girdle'' of the stone), and 24 on the ''pavilion'' (the lower half below the girdle). | |||
| Diamonds which are not cut to the specifications of Tolkowsky's round brilliant shape (or subsequent variations) are known as "fancy cuts." Popular fancy cuts include the ''baguette'' (from the French, resembling a ]), ''marquise'', ''princess'' (square outline), ''heart'', ''briolette'' (a form of the rose cut), and ''pear'' cuts. Generally speaking, these "fancy cuts" are not held to the same strict standards as Tolkowsky-derived round brilliants. Cuts are influenced heavily by fashion: the baguette cut — which accentuates a diamond's luster and downplays its fire — was all the rage during the ] period, whereas the princess cut — which accentuates a diamond's fire rather than its luster — is currently gaining popularity. The princess cut is also popular amongst diamond cutters: of all the cuts, it wastes the least of the original crystal. The past decades have seen the development of new diamond cuts, often based on a modification of an existing cut. Some of these include extra facets. These newly developed cuts are viewed by many as more of an attempt at brand differentiation by diamond sellers, than actual improvements to the state of the art. | |||
| ====Quality==== | |||
| The quality of a diamond's cut is widely considered the most important of the four Cs in determining the beauty of a diamond; indeed, it is commonly acknowledged that a well-cut diamond can appear to be of greater carat weight, and have clarity and color appear to be of better grade than they actually are. The skill with which a diamond is cut determines its ability to reflect and refract light. | |||
| In addition to carrying the most importance to a diamond's quality as a gemstone, the cut is also the most difficult to quantitatively judge. A number of factors, including proportion, ], and the relative angles of various facets, are determined by the quality of the cut and can affect the performance of a diamond. A poorly cut diamond with facets cut only a few degrees out of alignment can result in a poorly performing stone. For a round brilliant cut, there is a balance between "brilliance" and "fire." When a diamond is cut for too much "fire," it looks like a ], which gives off much more "fire" than real diamond. A well executed round brilliant cut should reflect most light out from the tabletop and make the diamond appear white when viewed from the top. An inferior cut will produce a stone that appears dark at the center and in some extreme cases the ring settings may show through the top of the diamond as shadows. | |||
| Several different theories on the "ideal" proportions of a diamond have been and continue to be advocated by professional gemologists. Recently, there has been a shift away from grading cut by the use of various angles and proportions toward measuring the performance of a cut stone. A number of specially modified viewers have been developed toward this end. One result of this trend is the rise of the phrase "]," describing a characteristic pattern observable on stones exhibiting high symmetry. Hearts and arrows diamonds trade at a 10 percent to 20 percent premium to otherwise comparable diamonds. | |||
| ====The cutting process==== | |||
| {{main|Diamond cutting}} | |||
| The process of shaping a rough diamond into a polished gemstone is both an art and a science. The choice of cut is often decided by the original shape of the rough stone, location of the inclusions and flaws to be eliminated, the preservation of the weight, popularity of certain shapes amongst consumers and many other considerations. The round brilliant cut is preferred when the crystal is an octahedron, as often two stones may be cut from one such crystal. Oddly shaped crystals such as macles are more likely to be cut in a ''fancy cut''—that is, a cut other than the round brilliant—which the particular crystal shape lends itself to. | |||
| Even with modern techniques, the cutting and polishing of a diamond crystal always results in a dramatic loss of weight; rarely is it less than 50%. Sometimes the cutters compromise and accept lesser proportions and symmetry in order to avoid inclusions or to preserve the carat rating. Since the per-carat price of diamond shifts around key milestones (such as 1.00 carat), many one-carat diamonds are the result of compromising "Cut" for "Carat." Some jewelry experts advise consumers to buy a 0.99 carat diamond for its better price or buy a 1.10 carat diamond for its better cut, avoiding a 1.00 carat diamond which is more likely to be a poorly cut stone. | |||
| ===Cleaning=== | |||
| {{main|Jewelry cleaning}} | |||
| Although it is not one of the four Cs, '''cleanliness''' affects a diamond's beauty as much as any of the four Cs. A clean diamond is more brilliant and fiery than the same diamond when it is "dirty". Dirt or grease on the top of a diamond reduces its luster. Water, dirt, or grease on the bottom of a diamond interferes with the diamond's brilliance and fire. Even a thin film absorbs some light that could have been reflected to the person looking at the diamond. Colored dye or smudges can affect the perceived color of a diamond. Historically, some jewellers' stones were misgraded due to smudges on the girdle, or dye on the culet. Current practice is to thoroughly clean a diamond before grading its color. | |||
| Maintaining a clean diamond can sometimes be difficult, as jewelry settings can obstruct cleaning efforts, and oils, grease, and other ] materials adhere well to a diamond's surface. Some jewellers provide their customers with ]-based cleaning kits; ]s are also popular. | |||
| Cleanliness does not affect the diamond's market value, as any competent jeweler will clean the diamond before offering it for sale. However, cleanliness might reflect a diamond's sentimental value: some jewellers have noted a correlation between ring cleanliness and marriage quality . | |||
| == History == | |||
| It is very believable that diamonds were in use in ] already in ], but surely were in use in ] . <!-- original report in the February issue of Archaeometry -->Diamonds were also recognized and mined in ], where significant alluvial deposits of the stone could then be found. The earliest written reference can be found in the ] text '']'' (completed around ]), which describes diamond's hardness, luster, and dispersion. Diamonds quickly became associated with divinity, being used to decorate religious ]s, and were believed to bring good fortune to those who carried them. Ownership was restricted among various ]s by color, with only kings allowed to own all colors of diamond. | |||
| Diamonds were traded to both the east and west of India, and were recognized by various cultures for their gemological and industrial uses. The ] writer ] noted diamond's ornamental uses, as well as its usefulness to ] due to its hardness, in his work '']''. In ], diamonds seem to have been used only for engraving ] and drilling holes in beads. Archeological evidence from ] suggests that diamonds were used as drill tips as early as the ]. In ], however, diamonds disappeared for almost 1,000 years following the rise of ] due to two effects: early ]s rejected diamonds due to their earlier use in ]s, and ] traders restricted the flow of trade between Europe and India. | |||
| ] | |||
| Until the late ], diamonds were most prized in their natural octahedral state, perhaps with the crystal surfaces polished to increase luster and remove foreign material. Around ], the flow of diamonds into Europe increased via ]'s trade network, with most flowing through the ] ports of ], ], and ]. Also around this time, the ] against cutting diamonds into gem shapes (established over 1,000 years earlier in the traditions of India) ended, allowing the development of diamond cutting technology to begin in earnest. By ], a guild of diamond polishers had been established at ]. Over the following centuries, various diamond cuts were introduced which increasingly demonstrated the fire and brilliance diamonds are treasured for today: the ''table cut'', the ''briolette'' (around ]), the ''rose cut'' (mid ]), and by the mid ], the ''Mazarin'', the first ] design. In ], ] determined an ''ideal'' round brilliant cut, a design that continues to set the standard for comparison for modern gems. However, the evolution of diamond cuts continues on to this day. | |||
| The rise in popularity of diamonds as gems seems to have paralleled increasing availability through European history. In the ], King ] established a law that only the king could own diamonds. However, within a century diamonds were popular gems among the moneyed ]ic and merchant classes, and by at latest ] had begun to be used in ]s. Popularity continued to rise as new cuts were developed that enhanced the diamond's aesthetic appeal, and has largely continued unabated to this day; diamonds have proven popular with all classes in society as their cost becomes within reach. A number of large diamonds have become historically significant objects, as their inclusion in various sets of ] and the purchase, sale, and sometimes theft of notable diamonds, have sometimes become politicized. | |||
| :''See also: ]'' | |||
| == The diamond industry == | |||
| ] | |||
| The diamond industry can be broadly separated into two basically distinct categories: one dealing with gem-grade diamonds and another for industrial-grade diamonds. While a large trade in both types of diamonds exists, the two markets act in dramatically different ways. | |||
| === Gem diamond industry === | |||
| A large trade in ]-grade diamonds exists. Unlike ]s such as ] or ], gem diamonds do not trade as a ]: there is a substantial mark-up in the sale of diamonds, and there is not a very active market for resale of diamonds. One hallmark of the trade in gem-quality diamonds is its remarkable concentration: wholesale trade and diamond cutting is limited to a few locations (most importantly ], ], ], and increasingly ]), and a single company — ] — controls over half of all trade in diamonds. | |||
| The De Beers company holds a clearly dominant position in the industry, and has done so since soon after its founding in ]. De Beers owns or controls a significant portion of the world's rough diamond production facilities (]) and distribution channels for gem-quality diamonds. 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 ]) in ], but presently the figure is estimated at around 60 percent. De Beers has used its ] position to establish strict price controls, and aggressively market diamonds directly to consumers in world markets. | |||
| The ''']''' is acknowledged as one of the most successful and innovative ones in history. ], the advertising firm retained by De Beers in the mid-], 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's multifaceted marketing campaign included ], advertising the diamond itself rather than the De Beers brand, and building associations with celebrities and royalty. This coordinated campaign has lasted decades and continues today; it is perhaps best captured by the now-familiar ] "a diamond is forever". | |||
| === 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 '']'', are destined for industrial use. In addition to mined diamonds, synthetic diamonds found industrial applications almost immediately after their invention in the ]; another 400 million carats (80,000 kg) of synthetic diamonds are produced annually for industrial use. | |||
| 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 ]), high-performance ], and limited use in specialized ]s. | |||
| With the continuing advances being made in the production of synthetic diamond, future applications are beginning to become feasible. Garnering much excitement is the possible use of diamond as a ] suitable to build ]s from, or the use of diamond as a ] in ]. Significant research efforts in ], ], and the ] are under way to capitalize on the potential offered by diamond's unique material properties, combined with increased quality and quantity of supply starting to become available from synthetic diamond manufacturers. | |||
| === Diamond supply chain === | |||
| ''See also: ]'' | |||
| 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. In fact, the amount of power which De Beers has consolidated historically prevented it from direct trade with the ], as its trade practices led to an ] for violating ] (the case was settled in ]). The concentration of power only loosens at the retail level, where diamonds are sold by a limited number of distributors, known as ]s, to jewelers around the world. | |||
| ] | |||
| ==== Sources ==== | |||
| Historically diamonds were known to be found only in alluvial deposits in ]; India led the world in diamond production from the time of their discovery in approximately the ] to the mid ], but the commercial potential of these sources has been exhausted. The first non-Indian diamond source was found in ] in ]. Today, most commercially viable diamond deposits are in ], notably in ], ], ], the ], and ]. There are also commercial deposits being actively mined in the ] of ], ] (mostly in ], for example ] and ]), Brazil, and in Northern and Western ]. Diamond prospectors continue to search the globe for diamond-bearing kimberlite and lamproite pipes. | |||
| 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. Diamonds sold through this process are known as ''']s''' or '''blood diamonds'''. In response to public concerns that their diamond purchases were contributing to war and human rights abuses in central Africa and west Africa, the diamond industry and diamond-trading nations introduced the ] in ], which is aimed at ensuring that conflict diamonds do not become intermixed with the diamonds not controlled by such rebel groups. The Kimberley Process provides 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. Although the Kimberly Process has been somewhat successful in limiting the number of conflict diamonds entering the market, conflict diamonds smuggled to market continue to persist to some degree. | |||
| 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 diamonds are sold for industrial use each year. In ], this constituted total production of nearly $9 billion in value. | |||
| ==== Distribution ==== | |||
| The ], 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; in whole, about two thirds of all rough diamonds pass through the company. DTC performs sophisticated sorting of rough diamonds into over 16,000 categories, and then sells bulk lots of rough diamonds to a limited number of sightholders a few times a year. | |||
| 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. Traditionally diamond cutting centers have been ], ], ], ], and ]. Recently, diamond cutting centers have been established in ] and ]. Cutting centers with lower ], notably Gujarat in 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 ] or ]. Demonstrating this, India produces 90% of all cut and polished diamonds by number, but only 55% by value. The recent expansion of this industry in India, employing low cost labor, has allowed smaller diamonds to be prepared as gems than was previously economically feasible. | |||
| Diamonds which have been prepared as gemstones are sold on diamond exchanges called '']s''. There are 24 registered diamond bourses. 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 ] the diamonds produced and released to the market were valued at $9 billion as rough diamonds, $14 billion after being cut and polished, $28 billion in wholesale diamond ], and retail sales of $57 billion. | |||
| ===Synthetics, simulants, and enhancements=== | |||
| {{main|Synthetic diamond}} | |||
| {{main|Diamond simulants}} | |||
| {{main|Diamond enhancement}} | |||
| The gemological and industrial uses of diamond have created a large demand for raw stones. A portion of this demand is now being met by ]s, man-made diamonds which have similar properties to natural diamonds. This process has historically produced industrial-grade diamonds, but synthetic diamond producers have recently begun to penetrate the gem diamond market. Diamonds have been manufactured synthetically for over fifty years. | |||
| 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 are known as ''diamond simulants''. The most familiar diamond simulant to most consumers is ] (commonly abbreviated as CZ); recently ] has also gained cachet as a popular diamond simulant. Both CZ and moissanite are synthetically produced for use as 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 all synthetic and simulant diamonds, and identify all enhanced natural diamonds. The established natural diamond industry has a vested interest in maintaining the distinction between natural diamonds and other diamonds, and has made significant investments toward that end. However, synthetic diamonds may one day be indistinguishable from natural diamonds, and new techniques for simulants (such as coating them with a very thin diamond-like layer of carbon) are making it harder to easily distinguish between simulants and real diamond. | |||
| ==Symbolism== | |||
| ] | |||
| Because of their extraordinary physical properties, diamonds have been used symbolically since near the time of their first discovery. Perhaps the earliest symbolic use of diamonds was as the eyes of ] devotional statues. The diamonds themselves were thought to be endowments from the gods and were therefore cherished. The point at which diamonds began to be associated with divinity is not known, but early texts indicate that it was recognized in ] since at least ]. It is said the ] believed diamonds were tears of the gods; the ] believed they were splinters of fallen stars. Many long dead cultures have sought to explain diamond's superlative properties through divine or mystical affiliations. | |||
| In western culture, diamonds are the traditional emblem of fearlessness and virtue. Today, diamonds are used to symbolize eternity and love, being often seen adorning ]s and sometimes ]s as well. The popularity of this modern tradition can be traced directly to the marketing campaigns of De Beers, starting in ]. The diamond engagement ring is, however, not an original invention of De Beers. It can be traced to the marriage of ] (then Archduke of ]) to ] in ]. Other early examples of betrothal jewels incorporating diamonds include the ''Bridal Crown of Blanche'' (ca. 1370-1380) and the ''Heftlein'' brooch of Vienna (ca. 1430-1440), a pictorial piece depicting a wedding couple. Inaccessibility of diamonds to the vast majority of the population limited the popularity of diamonds as betrothal jewels during this period. | |||
| The ] company further taps modern symbolism by offering to synthetically convert the carbonized remains of people or pets into "memorial diamonds." However, many people feel very uncomfortable at the thought of wearing the carbonized remains of people as jewelry. | |||
| Diamonds were also the symbol of ] in the ]. The ], one of the first and the foremost ] groups in the United States, used so-called ] as their ]. That were four diamonds arranged in a pattern to form a larger diamond. | |||
| The diamond is the ] for people born in the month of ], and is also used as the symbol of a sixty year ], such as a ] (see '']''). | |||
| ==External links== | |||
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| ==References== | |||
| * American Museum of Natural History. . Retrieved March 9, 2005. | |||
| * The Columbia Electronic Encyclopedia, Sixth Edition (2003). "Diamond". Retrieved March 9, 2005 at http://www.answers.com/topic/diamond. | |||
| * Cuellar, Fred. . Diamond Cutters International. Retrieved April 10, 2005. | |||
| * David, Joshua (September 2003). . ''Wired'', issue 11.09. | |||
| * De Beers Group. . Retrieved March 14, 2005. | |||
| * Epstein, Edward Jay (February 1982). (subscription required). ''The Atlantic Monthly''. | |||
| * Government of Gujarat (2004). . Retrieved March 14, 2005. | |||
| * Pricescope. . Retrieved March 4, 2005. | |||
| * Sque, Steve (March 8, 2005). . Retrieved March 10, 2005. | |||
| * Tolkowsky, Marcel (1919). ''Diamond Design: A Study of the Reflection and Refraction of Light in a Diamond.'' London: E. & F.N. Spon, Ltd. ( as edited by ], Seattle, 2001.) | |||
| * Tyson, Peter (November 2000). . Retrieved March 10, 2005. | |||
| * United Nations Department of Public Information (March 21, 2001). . Retrieved March 10, 2005. | |||
| * Yarnell, Amanda (February 2, 2004). . ''Chemical & Engineering News'', vol. 82, no. 5, pp 26–31. | |||
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Revision as of 14:49, 11 May 2005
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