Blue diamond is a type of

diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, ...

which exhibits all of the same inherent properties of the mineral except with the additional element of blue color in the stone. They are colored blue by trace amounts of boron that contaminate the crystalline lattice structure. Blue diamonds belong to a subcategory of diamonds called

fancy color diamonds 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 ...

, the generic name for diamonds that exhibit intense color.

Properties determining value

The same four basic parameters that govern the grading of all gemstones are used to grade blue diamonds–the four Cs of Connoisseurship: ''color'', ''clarity,'' ''cut'' and ''carat weight''. Color is considered the absolute most important criterion in grading a blue diamond and determining its value. However, the most valuable of blue diamonds also exhibit the highest clarity grades. There is no known blue diamond with a completely flawless (F) clarity grading, although several are known which are graded Internally Flawless (IF). One of the earliest mentioned blue diamonds is the Hope Diamond, a 45.52 carat fancy dark grayish-blue which is believed to have been discovered in India but whose first recorded presence was in 1666 by French gem merchant Jean-Baptiste Tavernier, after whom it was called the Tavernier Blue. Its last owner was famed jeweler Harry Winston before he donated it to the Smithsonian National Museum of Natural History in Washington, D.C. Colorless (“White”) diamonds have remained the most popular type of diamond through the millennia, but the existence of this blue diamond so long ago affirms the reality of the demand for fancy color diamonds over the years.

Color

In gemology, color is divided into three components: '' hue'', '' saturation'' and '' tone''. Blue diamonds occur in hues ranging from green-blue to gray-blue, with the primary hue necessarily being blue. Green and gray are the normal secondary hues that can be found in blue diamonds. Blue diamonds are considered most beautiful and valuable when there is no secondary color present but rather are a pure blue color. However, a pure blue diamond of light color may be considered less valuable than a green-blue or gray-blue diamond whose color is more vivid. The characteristic of color is very complex in blue diamonds for this reason. Most pure blue diamonds are

Type IIb In theoretical physics, type II string theory is a unified term that includes both type IIA strings and type IIB strings theories. Type II string theory accounts for two of the five consistent superstring theories in ten dimensions. Both theories ...

, meaning they contain either very few or a complete lack of nitrogen impurities.

Type Ia A Type Ia supernova (read: "type one-A") is a type of supernova that occurs in binary systems (two stars orbiting one another) in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white ...

blue stones contain a secondary hue and get their color from the presence of hydrogen.

Clarity

As with all diamonds, the loupe standard is used to grade clarity. This means that the inclusions are judged based on the appearance of the diamond under 10x magnification, and not how it would appear to the naked eye. Unlike in colorless diamonds, the clarity in blue diamonds has little effect on the diamond’s value. The exception is when there is an especially high clarity on a very vividly colored diamond. In this case, the clarity can add tremendous value.

Treatments

Blue diamonds are only considered rare and valuable if they are natural. The definition of a natural blue diamond is a blue diamond that was mined with its blue color already present. Since the 1950s, many methods have been developed to change a diamond’s appearance, including adding color to a colorless stone. These are considered ''enhanced'' diamonds and do not have the value or resale value of a natural blue diamond. Enhanced blue diamonds are not bought with the intention of investment or eventual resale. Synthetic blue diamonds have also been made, using the HPHT method.

Blue diamond mines

The earliest recorded blue diamond, the Hope Diamond, was discovered in

India India, officially the Republic of India ( Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the ...

, in the Kollur mine in the

Guntur Guntur () is a city and the administrative headquarters of Guntur district in the Indian state of Andhra Pradesh. Guntur is spread across 168.49 km square and is the third-largest city in the state. It is situated to the west of the ...

district of

Andhra Pradesh Andhra Pradesh (, abbr. AP) is a state in the south-eastern coastal region of India. It is the seventh-largest state by area covering an area of and tenth-most populous state with 49,386,799 inhabitants. It is bordered by Telangana to t ...

(which at the time was part of the Golconda kingdom), in the seventeenth century. However, blue diamonds have also been discovered in the Cullinan Mine in

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...

and the Golconda region. A few blue diamonds have been discovered in the Argyle Mine in

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to ...

as well, and are offered at their annual Argyle Tender when they are found. It is thought that blue diamonds, unlike most other diamonds, are formed in the lower part of Earth’s

mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...

, and that the boron creating their blue color originates from serpentinite carried down to the mantle by subducting ocean tectonic plates.

Blue diamonds in popular culture

Aside from the fabled curse of the Hope Diamond, blue diamonds do not yet represent a large part of world culture. However, as of 2015, blue diamonds have become the most sought-after gems at auction. This was instigated by the sale of the 9.75-carat fancy vivid blue "Zoe" diamond to Hong Kong billionaire Joseph Lau, who bought it for, and named it after, his young daughter, Zoe. An anthropomorphic character known as Blue Diamond is a member of the Great Diamond Authority in the TV show Steven Universe.

Notable blue diamonds

Gallery

File:Hope Diamond.jpg, The Hope Diamond File:HopeDiamondwithoutLighting.JPG, The Hope Diamond without lighting File:Hope diamond copy.jpg, Replica of the Hope Diamond File:SucherTavernierBlueReplicaRW.jpg, A replica of the Tavernier Blue File:Toison2010.png, Replica of the French Blue (Tavernier Blue) in a recreation of the

Order of the Golden Fleece The Distinguished Order of the Golden Fleece ( es, Insigne Orden del Toisón de Oro, german: Orden vom Goldenen Vlies) is a Catholic order of chivalry founded in Bruges by Philip the Good, Duke of Burgundy, in 1430, to celebrate his marriag ...

of King Louis XV of France

References

External links

{{Gemstone Diamond colors Blue diamonds