Natural gray diamonds, like all color diamonds, get their color from the inclusion of foreign elements during the diamond's formation under the Earth. In this case, the gray color is caused by the inclusion of hydrogen, although it may also be caused by boron. Regardless, these diamonds come in a variety of different shades and hues, which is what gives them their very unique color. Gray diamonds are sometimes called charcoal gray, steel, slate, silver and pigeon and have few intensities.
Their tones range from pewter and nickel to deeper hues like graphite and lead. Gray diamonds are mined in India, Russia, Brazil, South Africa and Australia, the home of the Argyle mine. Gray diamond production accounts for 2% of its color diamonds (the majority being champagne diamonds), although they are renowned for their pink diamonds. Interestingly, gray diamonds, like blue ones, are semiconductors of electricity, unlike the majority of diamonds, including most colors and colorless, which are non-conductors.
Fancy gray diamonds may be an unconventional diamond color but they hold a pronounced advantage over mainstream fancy colors because they are generally affordable for being more widely available. Unlike other popular fancy colored diamonds such as pink or orange, natural fancy gray diamonds consist of a neutral color whose iterations are so diverse that the range of gray hues is indeed sizeable. Other fancy colors can also couple with gray to form either a gray diamond with overtones, or secondary color modifiers. Blue is usually the most common overtone found in gray diamonds.
Natural gray diamonds derive their color from a hydrogen defect that makes the stones absorb equal quantities of all light wavelengths. Some fancy gray diamonds that are type IIb get their color from boron, which is well known for giving blue diamonds their distinct coloration. At present, it is not known how boron can produce both gray and blue diamonds as it is not apparent how these two diamond colors differ from each other structurally.
Unlike the majority of other kinds of fancy colored diamonds, gray diamonds have little or no saturation, their color is a function of their tones. Fancy gray diamonds occupy a wide scope of tones, ranging from lighter-hued pewter to deeper-hued graphite.
The diamond's colors appear will cooler or warmer according to whether they contain the cooler Blue or Green, or warmer Browns and Yellows.
Gray diamonds levels of color intensity are:
|Fancy Gray Diamond Intensity Scale|
|Very Light Gray|
|Fancy Light Gray|
|Fancy Deep Gray|
|Fancy Dark Gray|
The further along this spectrum you go, the richer and more intense the gray is to be seen in the diamond.
A gray diamond can lean either cool or warm depending on the kind of secondary color it is found with, those that are paired with Blue or Green are usually cool-toned and those that are paired with Browns or Yellows will be warm-toned.
From an anecdotal perspective, because gray diamonds are generally seen as possessing limited value compared to other types of natural fancy colored diamonds, in a marketing push to popularize their appeal to consumers, it is accepted among certain dealers in the trade that the more silvery the gray diamond, the more it will be worth. That said, stones that are a split grade or which have secondary color modifiers containing a much rarer color, such as a Fancy Blue Gray diamond or a Fancy Dark Violetish Gray diamond, are among the most desirable and valuable.
Tone refers to the lightness or darkness of a gray diamond, and the continuum in between. GIA grading does not make a distinction in tones, but to the eye a stone with darker tones may appear more intense in color. For someone looking for the appearance of a Fancy Dark Gray, a viable alternative may be a Fancy Gray diamond with a darker tone.
Gray diamonds do not have a marked tendency to exhibit fluorescence to UV light. On those occasions when they do show fluorescence, the result is usually faint and seldom medium blue. In the final analysis, the enhancement to a stone's aesthetics that fluorescence offers is entirely subjective.
Routine clarities for fancy gray diamonds tend to fall within the VS1 to I1 range, with SI1 to I1 being the most common. The greater majority of gray diamonds will be able to aptly conceal major inclusions. So even when a gray diamond has a clarity grade of I1 and beyond, its natural color is usually sufficient to help any internal flaws blend in seamlessly.
Natural gray diamonds can be found in virtually all shapes, including pear shapes, radiants, cushions and the classic round brilliant cut. In the case of gray diamonds, a round brilliant cut does not necessarily desaturate color as they usually have darker tones than other color diamonds. Take note of uneven color distributions as well (these will be noted on your GIA certificate), as they can certainly affect a diamond's appearance and value.
Similar to natural fancy champagne diamonds, fancy gray diamonds are generally considered to rank among the most affordable colored diamonds. They have not been favored by many consumers as the diamond of choice but a recent push by jewellers to cast these stones in a more aesthetically appealing light as part of fashion-forward jewellery designs has gained momentum. Those gray diamonds with exceptionally rare secondary color modifiers or which share a split grade with an exceptionally rare color, such as Blue or Violet, will command very high prices.
Dark diamonds, such as gray and black, were the first historical diamonds because the necessary technology for cutting diamond rough did not materialize until the 15th century. It is therefore fact that for much of antiquity, diamonds had a black, or graphite gray, appearance. Before the Renaissance, painters portrayed diamonds as having dark color in their renderings.
Natural fancy gray diamonds claim provenance in Australia, Brazil, India, Russia and South Africa. Two percent of the overall yield from the famed Argyle diamond mine in Western Australia, which produces more natural pink diamonds than any other mine in the world, consists of gray diamonds.
The Hope diamond - The Hope Diamond (previously "Le bleu de France") is the largest Deep Blue diamond in the world. The 45.52 carat Fancy Deep Grayish Blue VS1 diamond was mined in India and its dimensions are 25.60mm (length) x 21.78mm (width) x 12.00mm (depth).
Legend has it that the original form of the Hope Diamond was stolen from an eye of a sculpted statue of the goddess Sita in a Hindu temple. The temple priests then laid a curse on whoever might possess the missing stone and the "curse" of the Hope Diamond was born.The Hope Diamond and its associated curse were subsequently blamed for, amongst other fatalities, the beheadings of Louis XVI and Marie Antoinette. September 1812 is the earliest point when the history of the Hope Diamond can be definitively ascertained. A blue diamond with the same shape, size, and color as the Hope Diamond was recorded in the possession of the London diamond merchant Daniel Eliason. The Hope Diamond appeared in 1839 in a published catalog of the gem collection of prominent British banker Henry Philip Hope, who died the same year. His oldest nephew, Henry Thomas Hope, inherited the Hope Diamond. Following further inheritance issues and multiple changes in ownership, the Hope Diamond finally found its way into the hands of diamond merchant Harry Winston in 1949. On November 10, 1958, Winston donated the diamond to the Smithsonian. Traditionally, the Hope Diamond was in a necklace displayed in The Smithsonian in an oval setting surrounded by a series of white diamonds; however in 2009 it was displayed as a loose gem. On November 18th, 2010, the Hope Diamond was displayed in a new setting, with the design chosen from three possibilities in an online vote of more than 100,000 people. The Hope Diamond was shown in this setting for a year before being returned to its traditional one.
The Wittelsbach-Graff diamond - The Wittelsbach was a 35.56 carat Fancy Deep Grayish Blue VS2 diamond, cut with an unusual pattern of 82 facets. Since Madrid archives have been destroyed in the Spanish Civil War of 1936-1939, the diamond's earliest record dates from 1664, when it was given by Philip IV of Spain to his daughter Infanta Margareta Teresa, then 15, for her engagement to Emperor Leopold I of Austria. In, 1675 at the young age of 21, Infanta died after being weakened by too many miscarriages. Her husband inherited all her jewels and in turn, left them to his third wife, Empress Eleanor Magdalena, who passed the great blue diamond to her granddaughter, Archduchess Maria Amelia.
In 1964 it was bought by a private collector, and in 2008 the Wittelsbach Diamond was sold at a Christie's auction to the famous jeweller Laurence Graff for $23.4 million. Graff re-cut the diamond, losing 4.45 cararts, to 31.06 carats "to remove damage to the girdle and enhance the color." It is now a Fancy Deep Blue IF (Internally Flawless).
The Sultan of Morocco - The cushion cut, 35.27 carat, Fancy Grayish Blue Sultan of Morocco has an unknown clarity. It is believed the diamond emanated from India in the mid-19th century, however how it reached Europe, for how much, previous owner and the like are not known.
The name suggests a possible linkage with the ruling families of Morocco, the Sultans, however there is no evidence to confirm this. The diamond was definitely in the possession of the Yousupov family, a Russian noble family of Tartari descent, in 1840. In 1922, Prince Felix Yousupov, the last Yousupov prince and best known for his direct involvement in the murder of Rasputin, sold the diamond to Cartier's of New York. In 1972, the diamond was sold privately to an anonymous buyer in San Francisco, California for USD250,000. The buyer was apparently linked to the Vice President of the "Bud" Ehresman company who had the stone delivered to him by the famous jeweller, Laykin et cie, based in Los Angeles, California.
A colored diamond is generally rare when it exists as one color without any modifying colors. Gray diamonds can be found paired with Blue, Green, Violet, Pink, Purple, Champagne and Yellow. A gray diamond that is modified by a much rarer color, such as Blue or Violet, resulting in Fancy Blue Gray or Fancy Dark Violet Gray, will be much more rare and valuable than a Fancy Gray or Fancy Dark Gray diamond.
Depending on how they are set in jewellery, the darkness or lightness of the diamond can be more or less pronounced. Surrounding it with colorless diamonds really allows for the diamond color to shine through the most and take center stage in the piece, especially if there are secondary colors present in the center diamond.