Diamond (gemstone)

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Part of the series on Diamond

Material

Material properties Crystallographic defects Formation and surfacing

The 4 Cs

Carat · Clarity Color · Cut

Production

List of mines Diamond cutting The diamond industry De Beers

Cultural impact

History · Symbolism Famous diamonds

Imitations and enhancements

Synthetics · Simulants Enhancements

See also

Index of related articles Wikipedia Commons media

The introduction of this article is too short. To comply with Wikipedia's lead section guidelines, it should be expanded to summarize the article.

The diamond is perhaps the most valuable gemstone on earth. Its history as one extends from thousands of years in the past to form the basis of current detailed methods practiced in cutting and appraising diamond.

Contents 1 History 2 Gemological characteristics 2.1 Carat 2.2 Clarity 2.3 Color 2.4 Cut 2.4.1 Shape 2.4.2 Quality 2.4.3 Process 2.4.4 Light performance 2.5 Fluorescence 2.6 Cleaning 3 Symbolism and lore 4 The ring 5 Other facts 6 Notes 7 References

[edit] History

Early diamonds used as gemstones originated in India.^[1] Golconda served as an important center for diamonds in central India.^[2] Diamonds then were exported to other parts of the world, including Europe.^[1]

Early references to diamonds in India come from Sanskrit texts.^[3] The Arthashastra of Kautilya mentions diamond trade in India.^[4] India remained the only major source of diamonds in the world until the discovery of diamonds in Brazil.^[4] Buddhist works dating from the 4th century BC as a well-known and precious stone but don't mention the details of diamond cutting.^[5] Another Indian description written at the beginning of the 3rd century describes strength, regularity, brilliance, ability to scratch metals, and good refractive properties as the desirable qualities of a diamond.^[6] A Chinese work from the 3rd century BC mentions: "Foreigners wear it [diamond] in the belief that it can ward off evil influences".^[6] The Chinese, who did not find diamonds in their country, initially did not use diamond as a jewel but used as a "jade cutting knife".^[6]

The diamonds reached ancient Rome from India.^[3] Diamonds were also discovered in 700 AD in Borneo, and were used by the traders of southeast Asia.^[3] But India remained the exclusive source of diamonds to Europe until the 18th century.^[3] With the depletion of India's diamond resources the exploration for seeking out and finding diamonds from other parts of the world began, which led to discoveries in Brazil (1725) and South Africa (Kimberley, 1867).^[1] South Africa became the favored center for diamond resources, and quickly rose as the world's biggest diamond producer.^[1]

Diamonds were traded to both the east and west of India and were recognized by various cultures for their gemological or industrial uses. In his work Naturalis Historia, the Roman writer Pliny the Elder noted diamond's ornamental uses, as well as its usefulness to engravers because of its hardness. It is however highly doubtful that Pliny actually meant diamonds and it is assumed that in fact several different minerals such as Corundum, Spinel, or even a mixture with Magnetite were all referred to by the word "adamas".^[7]

[edit] Gemological characteristics

The most familiar usage of diamonds today is as gemstones used for adornment a usage which dates back into antiquity. The dispersion of white light into spectral colors, is the primary gemological characteristic of gem diamonds. 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. 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.

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 (300 mg), VS2 clarity, F color, excellent cut round brilliant, is enough to reasonably establish an expected price range. More detailed information from within each characteristic is 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.

Other characteristics not described by the four Cs influence the value or appearance of a gem diamond. These characteristics include physical characteristics such as the presence of fluorescence, 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.

There are three major non-profit gemological associations which grade and provide reports or certificates ("certs") on diamonds; while carat weight and cut angles are mathematically defined, the clarity and color are judged by the trained human eye and are therefore open to slight variance in interpretation. The associations are listed below.

• Gemological Institute of America (GIA) was the first laboratory in America to issue modern diamond reports,^[8] and is held in high regard amongst gemologists for its consistent, conservative grading.
• American Gem Society (AGS) is not as widely recognized nor as old as the GIA but garners a high reputation. The AGS employs a number system for grading cut quality, color grade, and clarity. The highest grade being '0', and the lowest being '10'.
• Diamond High Council (HRD) Official certification laboratory of the Belgian diamond industry, located in Antwerp. Antwerp World Diamond Center

Within the last two decades, a number of for-profit gemological grading laboratories have also been established, many of them also based in Antwerp or New York. These entities serve to provide similar services as the non-profit associations above, but in a less expensive and more timely fashion. They produce certificates that are similar in detail to the GIA's.

[edit] Carat

The carat weight measures the mass of a diamond. One carat is defined as 200 milligrams (about 0.007 ounce avoirdupois). The point unit—equal to one one-hundredth of a carat (0.01 carat, or 2 mg)—is commonly used for diamonds of less than one carat. All else being equal, the price per carat increases with carat weight, since larger diamonds are both rarer and more desirable for use as gemstones.

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 may have a significantly lower price per carat than a comparable 1.05 carat diamond, because of differences in demand.

A weekly diamond price list, the Rapaport Diamond Report is published by Martin Rapaport, CEO of Rapaport Group of New York, for different diamond cuts, clarity and weights.^[9] It is currently considered the de-facto retail price baseline. Jewelers often trade diamonds at negotiated discounts off the Rapaport price (e.g., "R -3%").

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 solitaire earrings, for example, are usually quoted in t.c.w. when placed for sale, indicating the mass of the diamonds in both earrings and not each individual diamond. T.c.w. is also widely used for diamond necklaces, bracelets and other similar jewelry pieces.

[edit] Clarity

Main article: 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 Gemological Institute of America (GIA) and other organizations have developed systems to grade clarity, which are based on those inclusions which are visible to a trained professional when a diamond is viewed 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 one or more visible inclusions. 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.

Diamonds are graded by the major societies on a scale ranging from flawless to imperfect.

[edit] Color

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Main article: Diamond color

A chemically pure and structurally perfect diamond is perfectly transparent with no hue, 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 crystal lattice. 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 Hope Diamond) can be dramatically more valuable. The Aurora Diamond Collection displays a spectacular array of naturally colored diamonds.

Most diamonds used as gemstones are basically transparent with little tint, or white diamonds. The most common impurity, nitrogen, 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 from 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 bright yellow coloration), which has been widely adopted in the industry and is universally recognized, superseding several older systems once used in different countries. The GIA system uses a benchmark set of natural diamonds of known color grade, along with standardized and carefully controlled lighting conditions. Diamonds with higher color grades are rarer, in higher demand, and therefore more expensive, than lower color grades. Oddly enough, diamonds graded Z are also rare, and the bright yellow color is also highly valued. Diamonds graded D-F are considered "colorless", G-J are considered "near-colorless", K-M are "slightly colored". N-Y usually appear light yellow or brown.

In contrast to yellow or brown hues, diamonds of other colors are more rare and 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 because of the relative rarity of colored diamonds.

[edit] Cut

Main article: Diamond cut

Diamond cutting is the art and science of creating a gem-quality diamond out of mined rough. 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 the quality of workmanship and the angles to which a diamond is cut. Often diamond cut is confused with "shape".

There are mathematical guidelines for the angles and length ratios at which the diamond is supposed to be cut in order to reflect the maximum amount of light. Round brilliant diamonds, the most common, are guided by these specific guidelines, though fancy cut stones are not able to be as accurately guided by mathematical specifics.

The techniques for cutting diamonds have been developed over hundreds of years, with perhaps the greatest achievements made in 1919 by mathematician and gem enthusiast Marcel Tolkowsky. He developed the round brilliant cut 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), and 24 on the pavilion (the lower half). The girdle is the thin middle part. The function of the crown is to diffuse light into various colors and the pavilion's function to reflect light back through the top of the diamond.

Tolkowsky defines the ideal dimensions to have:

• Table percentage (table diameter divided by overall diameter) = 53%
• Depth percentage (Overall depth divided by the overall diameter) = 59.3%
• Pavilion Angle (Angle between the girdle and the pavilion) = 40.75°
• Crown Angle (Angle between the girdle and the crown) = 34.5°
• Pavilion Depth (Depth of pavilion divided by overall diameter) = 43.1%
• Crown Depth (Depth of crown divided by crown diameter) = 16.2%

The culet is the tiny point or facet at the bottom of the diamond. This should be a negligible diameter, otherwise light leaks out of the bottom. Tolkowsky's ideal dimensions did not include a culet. However, a thin culet is required in reality in order to prevent the diamond from easily chipping in the setting. A normal culet should be about 1%–2% of the overall diameter.

The further the diamond's characteristics are from Tolkowsky's ideal, the less light will be reflected. However, there is a small range in which the diamond can be considered "ideal." Today, because of the relative importance of carat weight in society, many diamonds are often intentionally cut poorly to increase carat weight. There is a financial premium for a diamond that weighs the magical 1.0 carat, so often the girdle is made thicker or the depth is increased. Neither of these tactics make the diamond appear any bigger, and they greatly reduce the sparkle of the diamond. So a poorly cut 1.0 carat diamond may have the same diameter and appear as large as a 0.85 carat diamond. The depth percentage is the overall quickest indication of the quality of the cut of a round brilliant. "Ideal" round brilliant diamonds should not have a depth percentage greater than 62.5%. Another quick indication is the overall diameter. Typically a round brilliant 1.0 carat diamond should have a diameter of about 6.5 mm. Mathematically, the diameter in millimeters of a round brilliant should approximately equal 6.5 times the cube root of carat weight, or 11.1 times the cube root of gram weight, or 1.4 times the cube root of point weight.

Ideal cuts can be controversial as the definitions of brilliance and beauty are very subjective.

Tolkowsky's mathematical model is now superseded by the GIA Facetware software that is the culmination of 20 years of studies on diamond cuts.

New diamond cuts are now all the rage in the diamond industry as for example a design invented in 2003 and called the Genesis cut. This cut differs in shape from the more traditional cuts in its concave surfaces and angles and resembles a 4-pointed star.

[edit] 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.

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, meaning rod or loaf of bread), marquise, princess cut (square outline), heart, briolette (a form of the rose cut), and pear cuts. Newer cuts that have been introduced into the jewelry industry are the "cushion" "radiant" (similar to princess cuts, but with rounded edges instead of square edges) and Asscher cuts. Many fancy colored diamonds are now being cut according to these new styles. Generally speaking, these "fancy cuts" are not held to the same strict standards as Tolkowsky-derived round brilliants and there are less specific mathematical guidelines of angles which determine a well-cut stone. 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 Art Deco 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.

[edit] 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, polish, symmetry, 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 cubic zirconia, which gives off much more "fire" than real diamond. A well-executed round brilliant cut should reflect light upwards 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 various owners of patents on machines to view how well a diamond is cut. These advocate 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 and machines have been developed toward this end. Hearts and Arrows viewers test for the "hearts and arrows" characteristic pattern observable in stones exhibiting high symmetry and particular cut angles. Closely related to Hearts and Arrows viewers is the ASET which tests for light leakage, light return, and proportions. The ASET (and computer simulations of the ASET) are used to test for AGS cut grade. These viewers and machines often help sellers demonstrate the light performance results of the diamond in addition to the traditional 4 Cs. Detractors see these machines as marketing tools rather than as scientific tools.

The GIA has developed a set of criteria for grading the cut of round brilliant stones that is now the standard in the diamond industry and is called Facetware.

[edit] Process

Main article: 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.

[edit] Light performance

In the gem trade the term light performance is used to describe how well a polished diamond will return light to the viewer. There are three light properties which are described in relation to light performance; brilliance, fire, and scintillation. Brilliance refers to the white light reflections from the external and internal facet surfaces. Fire refers to the spectral colors which are produced as a result of the diamond dispersing the white light. Scintillation refers to the small flashes of light that are seen when the diamond, light source or the viewer is moved. A diamond that is cut and polished to produce a high level of these qualities is said to be high in light performance.

The setting diamonds are placed in also affect the performance of light through a diamond. The 3 most commonly used settings are: Prong, Bezel, and Channel. Prong settings are the most popular setting for diamond jewelry. The prong setting consists of four or six 'claws' that cradle the diamond, allowing the maximum amount of light to enter from all angles, allowing the diamonds to appear larger and more brilliant. In bezel settings the diamond or gemstone is completely surrounded by a rim of metal, which can be molded into any shape to accommodate the stone. Used to set earrings, necklaces, bracelets, and rings, bezel settings can have open or closed backs, and generally can be molded to allow a lot of light to pass through. Channel settings set the stones right next to each other with no metal separating them. This setting is mostly used in wedding and anniversary bands. The outer ridge is then worked over the edges of the stones to create a smooth exterior surface. This also protects the girdle area of the stone.

[edit] Fluorescence

About a third of all diamonds will glow under ultraviolet light, usually a blue color which may be noticeable under a black light or strong sunlight. According to the GIA, who reviewed a random sample of 26,010 natural diamonds, 65% of the diamonds in the sample had no fluorescence. Of the 35% that did have fluorescence, 97% had blue fluorescence of which 38% had faint blue fluorescence and 62% had fluorescence that ranged from medium to very strong blue. Other colors diamonds can fluoresce are green, yellow, and red but are very rare and are sometimes a combination of the colors such as blue-green or orange. Some diamonds with "very strong" fluorescence can have a "milky" or "oily" look to them, but they are also very rare and are termed "overblues." Their study concluded that with the exception of "overblues" and yellow fluorescent diamonds, fluorescence had little effect on transparency and that the strong and very strong blue fluorescent diamonds on average had better color appearance than non-fluorescent stones. Since blue is a complementary color to yellow and can appear to cancel it out, strong blue fluorescence had especially better color appearance with lower color graded diamonds that have a slight yellowish tint such as "I" color or "J" color but had little effect on the more colorless "D" through "F" color grades.^[10]

[edit] Cleaning

Main article: Jewellery cleaning

Cleanliness heavily affects a diamond's beauty. 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 jewelers' stones were misgraded because of smudges on the girdle, or dye on the culet. Current practice is to clean a diamond thoroughly before grading its color.

Maintaining a clean diamond can sometimes be difficult as jewelry settings can obstruct cleaning efforts and oils, grease, and other hydrophobic materials adhere well to a diamond's surface. Many jewelers use steam cleaners. Some jewelers provide their customers with ammonia-based cleaning kits; ultrasonic cleaners are also popular.

[edit] Symbolism and lore

Historically, it has been claimed that diamonds possess several supernatural powers:

• A diamond gives victory to him who carries it bound on his left arm, no matter the number of enemies.^[11]
• Panics, pestilences, enchantments, all fly before it; hence, it is good for sleepwalkers and the insane.^[11]
• It deprives lodestone and magnets of their virtue (i.e., ability to attract iron).^[11]
• Arabic diamonds are said to attract iron greater than a magnet.^[11]
• A diamond's hardiness can only be broken by smearing it with fresh goat's blood.^[11]
• In traditional Hinduism one should avoid contact with a diamond which surface area is damaged by a crack, a crowfoot, round, dull, speckled area or which is black-blue, flat, and if uncut, other than the (ideal) hexagonal shape.^[12]

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 Hindu devotional statues.^[13] In Hinduism Indra uses Vajrayudham or the thunderbolt as his primary weapon. Vajra is the word for diamond and ayudham means weapon in Sanskrit. Another name for it was Agira which means fire or the sun. In fact there are 14 names counted to be given to a diamond in traditional Hinduism.^[12]

The oldest dated printed book in the world is called the Diamond Sutra, dates from AD 868 and was found in a cave in North-West China. Sutra's are most used to describe the teachings of Buddha. In this case the title of the Sutra refers not to the diamond itself but to a 'diamond blade that will cut through worldly illusion to illuminate what is real and everlasting'. Jewel imagery forms a central part of Buddhism: the triple-jewel represent 'Buddha', his teachings 'Dharma' and the spiritual community 'Shangha'. The book presently resides in the British Library.^[14]

Many cultures use divine intervention to explain the origin and creation of gemstones, and diamonds were no exception to this. In Greek mythology for example it was the youth on the island of Crete that disturbed Zeus and who were then (as a form of punishment) transformed into the adamas.^[15]

Philosophers however had a more naturalistic approach to explain the origin of gems: Plato for example believed gemstones were a consequence of fermentation in the stars, where a diamond actually formed the kernel of gold-bearing mass.^[15] In fact often diamonds were linked to gold, which may have found its origin in the joint occurrence of diamonds with quartzite, quartz veins and an occasional occurrence of gold in them.^[16]

In later times, Robert Boyle actually believed that gems (including a diamond) were formed of clear, transparent water, and that their colors and characteristics were derived from their metallic spirit.^[17]

[edit] The ring

Main article: Engagement ring

The origin of the custom to use diamonds in rings, and more recently, in engagement rings, can be traced back to the Middle Ages and even the Romans. The Romans valued the diamond entirely on account of its supernatural powers. Pliny wrote that a diamond baffles poison, keeps off insanity and dispels vain fears.^[16] The medieval Italians copied these beliefs and added some to it: they called it the "Pietra della Reconciliazone" because it maintained concord between husband and wife. On this account it was recommended as the stone to be set in wedding (or espousal) rings—not on account of its beauty therefore, which was described by Isidore of Seville as a small stone devoid of beauty.^[16]

In more recent times a Parisian Oracle of mystic subjects, the Baron d'Orchamps, announced the diamond, if worn on the left (hand) warded off evil influences and attracted good fortune and since he had fashionable clients the word spread and the wearing of the diamond on the left hand became in itself a fashion.^[18]

One of the first occurrences of the diamond engagement (or wedding) ring can be traced back to the marriage of Maximilian I (then Archduke of Austria) to Mary of Burgundy in 1477.^[19] Other early examples of betrothal jewels incorporating diamonds include the Bridal Crown of Blanche (ca. 1370–80)^[19] and the Heftlein brooch of Vienna (ca. 1430–40),^[19] a pictorial piece depicting a wedding couple.

The popularity of the diamond ring as an engagement ring for a much wider audience can be traced directly to the marketing campaigns of De Beers, starting in 1938.^[20] Such a campaign had become necessary to sell the large quantity of diamonds suddenly available because of the large diamond finds particularly in South Africa.

[edit] Other facts

The diamond is the birthstone for people born in the month of April, and is also used as the symbol of a sixty-year anniversary, such as a Diamond Jubilee (see hierarchy of precious substances). In a system of heraldry by gemstone occasionally used in the past for the arms of nobles, diamond was used to represent the color sable, or black.^[21]

Diamonds are a common focus of fiction. Notable pieces of fiction include Ian Fleming's Diamonds Are Forever (1956), Arthur C. Clarke's 2061: Odyssey Three (1988), F. Scott Fitzgerald's "The Diamond as Big As the Ritz" (1922), and Neal Stephenson's The Diamond Age (1995). In addition, diamonds are the subject of various myths and legends.

[edit] Notes

[edit] References

• Wenk, Hans-Rudolf; et al. (2003). Minerals: Their Constitution and Origin. Cambridge University Press. ISBN 0521529581. 
• Dickinson, Joan Y. (2001). The Book of Diamonds. Dover Publications. ISBN 0486418162. 
• Lee, Sunggyu (2006). Encyclopedia of Chemical Processing. CRC Press. ISBN 0824755634.