"Diamond" comes from the Greek adamao, transliterated as "adamao," "I tame" or "I subdue." The adjective "adamas" was used to describe the hardest substance known, and eventually became synonymous with diamond. Diamond is the hardest natural material known to man - its hardness set to 10 (hardest) on Mohs scale of mineral hardness The hardness of diamonds contributes to its suitability as a gemstone. 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 because of its resistance to scratching—perhaps contributing to its popularity as the preferred gem in an engagementring or wedding ring, which are often worn every day.
Mines
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. They are mined from kimberlite and lamproite volcanic pipes, which brought to the surface the diamond crystals from deep in the Earth where the high pressure and temperature enables the formation of the crystals.
Cullinan - The largest
The Cullinan Diamond, found by Frederick Wells, surface manager of the Premier Diamond Mining Company in Cullinan, Gauteng, Souh Africa, on January 26, 1905, is the largest rough gem-quality diamond ever found, at 3,106.75 carats (621.35 g). In 1905, transport from South Africa to England posed a bit of a problem with regard to security. Detectives from London were placed upon a steamer ship that was rumoured to carry the stone, but this was a diversionary tactic. The stone on that ship was a fake, meant to attract those who would be interested in stealing it. The actual diamond was sent to England in a plain box via parcel post.
The mine officer holding the Cullinan
Rumours abound of a second half of the Cullinan diamond, as there are certain indications that the diamond was part of a larger crystal. It is suggested that before Frederick Wells sold the diamond to Sir Thomas Cullinan he broke off a piece which sized in at about 1,500 to 2,000 carats (300 to 400 g). If this were true, the original Cullinan diamond would have weighed approximately 5,000 carats (1 kg)
The stone was bought and presented to King Edward VII. It was cut into three large parts by Asscher Brothers of Amsterdam, and eventually into some 11 large gem-quality stones and a number of smaller fragments.
Cullinan 1
The largest polished gem from the stone is named Cullinan I or the Great Star of Africa , and at 530.2 carats (106.04 g) was the largest polished diamond in the world until the 1985 discovery of the Golden Jubilee diamond (545.67 cts), also from the Premier Mine. Cullinan I is now mounted in the head of the Sceptre with the Cross. The second largest gem from the Cullinan stone, Cullinan II or the Lesser Star of Africa, at 317.4 carats (63.48 g), is the third largest polished diamond in the world and is also part of the British crown jewels, as it forms a part of the Imperial State Crown. Both gems are on display at the Tower of London, as parts of the Crown Jewels of the United Kingdom.
The Golden Jubilee
The Golden Jubilee is currently the largest faceted diamond in the world. Since 1908, Cullinan I, also known as the Great Star of Africa, had held the title, which changed following the 1985 discovery of a large brown diamond of 546 carats (151 g) in the prolific blue ground of the Premier mine in South Africa; the diamond would later be cut and named The Golden Jubilee, with an as-of today unsurpassed weight of 545.67 carats (109.13 g)
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The "Unnamed Brown", as the Golden Jubilee was first known, was considered something of an ugly duckling by most. It was given to Gabriel Arellano (DCW) by De Beers for the purpose of testing special tools and cutting methods which had been developed for intended use on the flawless D-colour ("colourless") Centenary. These tools and methods had never been tested before, and the "Unnamed Brown" seemed the perfect guinea pig; it would be of no great loss should something go amiss.
To the surprise of all concerned, what resulted was a yellow-brown diamond in a fire rose cushion cut, outweighing Cullinan I by 15.37 carats (3.07 g). The stone remained largely unknown to the outside world, as the Golden Jubilee's sister, the Centenary, had already been selected and promoted to herald De Beer's centennial celebrations in 1988.
The unnamed diamond had earlier been brought to Thailand by the Thai Diamond Manufacturers Association to be exhibited in the Thai Board of Investment Exhibition in Laem Chabang. There was a mile-long queue to see the diamond, which outshone all other exhibits.
While the current whereabouts of the Centenary are unknown, the Golden Jubilee is known to have been purchased from De Beers by a group led by Henry Ho of Thailand in 1995. The diamond was brought to Pope John Paul II in the Vatican to receive the papal blessing. It was also blessed by the Supreme Buddhist Patriarch and the Supreme Imam in Thailand. The Golden Jubilee Diamond was named by King Bhumibol Adulyadej and given to him in honour of his 50th coronation anniversary.
Quality
The value of a diamond is based on the 4 c's
Carat
The carat weight measures the mass of a diamond. One carat is defined as 0.2 grams 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 value of a diamond increases exponentially in relation to 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.
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. Clarity gradings 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.
IF
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Internally Flawless - under 10 x magnification, the diamond is flauwless
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VVS
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Very Very Slightly included - under 10 x magnification difficult to be visible to a trained professional
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VS
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Very Slightly included - under 10 x magnification difficult to be visible to a trained professional
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SI
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Slightly Included - under 10 x magnification is visible to a trained professional
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P I
(Piqué I)
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Included - visible without magnification to a trained proffesional
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P II
(Piqué II)
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Included - Easily visible without magnification
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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 can be dramatically more valuable.
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 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 bright yellow coloration), which has been widely adopted in the industry and is universally recognized, superseding several older systems once used in different countries. 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.
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.
Colour scale:
CIBJO*
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GIA**
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Very fine white
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D / E
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fine white
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F / G
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white
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H
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tinted white
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I /J
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tinted colour
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K,L,M, N, ...Z
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*
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CIBJO = Confederation Internationale de la Bijouterie, Joaillerie, Orfevrerie, Des Diamants Perles et Pierres.
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**
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GIA = Gemological Institute of America
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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. 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.
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 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. One of these is a diamond cut called Pristine Hearts which though round shaped has got a beautiful heart visible through table as well as the bottom side.
Shape
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.
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