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Diamond

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105 carats

A diamond (from the ancient Greek adámas, meaning "unbreakable," "proper," or "unalterable") is one of the best-known and most sought-after gemstones. Diamonds have been known to humankind and used as decorative items since ancient times; some of the earliest references can be traced to India.

The hardness of diamond and its high dispersion of light – giving the diamond its characteristic "fire" – make it useful for industrial applications and desirable as jewellery.

Perhaps the most famous use of the diamond in jewellery is in engagement rings, which became popular in the early to mid 20th century due to an advertising campaign by the De Beers company, though diamond rings have been used to symbolize engagements since at least the 15th century.
4 photos

Diamond Gemstones by Colour

This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
 
 
 
 

Diamond Gemstones by Size

This table shows distribution of Diamond gemstone sizes that are listed on this site. This can give a good indication as to the general availability of this gemstone in different sizes.
Contributed photos
Lightest:0.30 cts
Heaviest:105 cts
Average:37.83 cts
Total photos:4
Do you have a larger Diamond? Why not upload a photo?
Significant stones
Cullinan I (Star of Africa)530 cts
Orlov Diamond190 cts
Ahmed-Abad157 cts
Florentine137 cts
Tiffany (Yellow)129 cts
0.30ct to 10.77ct10.77ct to 21.24ct21.24ct to 31.71ct31.71ct to 42.18ct42.18ct to 52.65ct52.65ct to 63.12ct63.12ct to 73.59ct73.59ct to 84.06ct84.06ct to 94.53ct94.53ct to 105.00ct
General Information
Chemical Formula
C
Walter Schumann, Gemstones of the world (2001)
More from other references
Significant stones
ImageNameWeightCountry of OriginCurrent Owner
Cullinan I (Star of Africa)530.20 ctsSouth AfricaBritish Crown
Orlov Diamond190.00 ctsIndiaKremlin Diamond Fund
Ahmed-Abad157.25 ctsIndia
Florentine137.27 ctsIndia
Tiffany (Yellow)128.54 ctsSouth AfricaTiffany & Co.
Portuguese127.01 cts
Koh-i-Noor105.60 ctsIndiaThe British Crown
Shah88.70 ctsIndia
Click here to view all significant Diamond gemstones
Diamond Treatments
The irradiation of a type Ia diamond,
followed by heating at 800°C, resulted in diamonds having a yellow or orange colour. This treatment is easily detected because an absorption line
is also produced between 594 and 595 nm; this absorption is very rarely seen in a faceted natural fancy-coloured diamond. With a type Ib diamond, either natural or synthetic HPHT, irradiation followed by annealing produces a treated pink diamond.
Radiation Followed by High Temperature (c.1400 °C) can give the diamond an attractive green colour.
A tinted yellow (cape) diamond could be given a fancy canary yellow colour by HPHT processing.Following this processing, it is possible to subject the diamond to irradiation and annealing at 800 °C. It gives the diamond a pink or mauve colour.
Diamond Simulants
Strontium titanate is an artificial gemstone that has been used as a diamond simulant.
Synthetic Diamond
Synthetic diamond: Colourless, yellow, brown, green, blue, red, pink; Transparent; Hardness 10; RI 2.417; Opt. isotropic; SG 3.52; Perfect cleavage; Fluorescence: SW - distinct yellow, yellowish-green or whitish-yellow; Inclusions: metallic residues (partly magnetic), internal growth and colour zoning - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 31
Physical Properties of Diamond
Mohs Hardness10
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Specific Gravity3.50 to 3.53
Walter Schumann, Gemstones of the world (2001)
More from other references
Cleavage QualityPerfect
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
More from other references
FractureConchoidal,Splintery
Walter Schumann, Gemstones of the world (2001)
More from other references
Heat SensitivityHigh temperatures can induce etchings on the facets. Therefore special care must be taken during soldering!
Walter Schumann, Gemstones of the world (2001)
Refractive Index2.417 to 2.419
Walter Schumann, Gemstones of the world (2001)
More from other references
Optical CharacterIsotropic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Anomalous double refractionMore from other references
PleochroismNone
Walter Schumann, Gemstones of the world (2001)
Dispersion
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