Diamond

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Fancy Intense Green Yellow Diamond
0.19 carats
© Fancydiamonds.net

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.

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:0.01 cts
Heaviest:189.62 cts
Average:2.85 cts
Total photos:316
Do you have a larger Diamond? Why not upload a photo?
Significant stones
Cullinan I (Star of Africa)530 cts
Orlov Diamond190 cts
0.01ct to 18.97ct18.97ct to 37.93ct37.93ct to 56.89ct56.89ct to 75.85ct75.85ct to 94.82ct94.82ct to 113.78ct113.78ct to 132.74ct132.74ct to 151.70ct151.70ct to 170.66ct170.66ct to 189.62ct
General Information
Varieties/Types:
Nano-Polycrystalline Diamond - An synthetic polycrystalline diamond.
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
Darya-ye Noor Diamond182.00 ctsIndiaMuseum of Central Bank of Iran
Ahmed-Abad157.25 ctsIndia
Florentine137.27 ctsIndia
Tiffany (Yellow)128.54 ctsSouth AfricaTiffany & Co.
Portuguese127.01 cts
Koh-i-Noor105.60 ctsIndiaThe British Crown
Click here to view all significant Diamond gemstones
Photos of natural/un-cut material from mindat.org
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
An enormous number of materials, both natural and artificial, have been used as diamond simulants for thousands of years.

Glass, quartz and other gemstones have been used throughout recorded history to simulate Diamonds, but a true diamond simulant must have the high dispersion that is characteristic of diamond, and ideally be hard enough to be used as a gemstone.

lead glass - a glass with a high refractive index, has been used to simulate diamond for a very long time, it is of course much softer than diamond.

cubic zirconia, or CZ, is probably the most economically important diamond simulant, in use since the 1970s it is very similar visually to diamond but very low cost to produce.

Strontium titanate is an artificial gemstone that was used frequently as a diamond simulant from the mid 1950s until the 1970s.

Yttrium Aluminium Garnet or YAG, and Gadolinium Gallium Garnet or GGG, are two artificial garnet-type gemstones that were frequently used as diamond simulants in the early to mid 1970s, until the availability of cheap Cubic Zirconia.

Moissanite, or silicon carbide, is a much more recent synthetic gemstone, having been first produced commercially in 1998. Unlike most other diamond simulants, it has a very high hardness - second only to diamond itself in the gem world, with higher refractive index and dispersion than diamond.
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)
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Specific Gravity3.50 to 3.53
Walter Schumann, Gemstones of the world (2001)
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Cleavage QualityPerfect
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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FractureConchoidal,Splintery
Walter Schumann, Gemstones of the world (2001)
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Heat SensitivityHigh temperatures can induce etchings on the facets. Therefore special care must be taken during soldering!
Walter Schumann, Gemstones of the world (2001)
Optical Properties of Diamond
Refractive Index2.417 to 2.419
Walter Schumann, Gemstones of the world (2001)
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Optical CharacterIsotropic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Anomalous double refractionMore from other references
PleochroismNone
Walter Schumann, Gemstones of the world (2001)
Dispersion0.044
Michael O’Donoghue, Gems, Sixth Edition (2006)
More from other references
Colour
Colour (General)Colorless, yellow, brown, rarely green, blue, reddish, orange black
Walter Schumann, Gemstones of the world (2001)
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TransparencyTransparent,Translucent,Opaque
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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LustreAdamantine,Greasy
Michael O’Donoghue, Gems, Sixth Edition (2006) Adamantine to greasyMore from other references
Fluorescence & other light emissions
Fluorescence (General)Very variable: Colorless and yellow: mostly blue; Brownish and greenish: often green
Walter Schumann, Gemstones of the world (2001)
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Fluorescence (Short Wave UV)Weaker reaction if any. Yellow: rare weak yellow to orange. Blue: rare yellowish to bluish
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Fluorescence (Long-Wave UV)Usually blue (and yellow phosphorescence). Colorless (near-colorless): tylically strong blue. Yellow: inert to strong blue, yellow (also green, rarely orange). Pink (and red): mostly blue (yellowish to orangy phosphorescence). Blue: rare orangy. Green, brown: green
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Fluorescence (X-RAY)Most diamonds show a rather uniform bluish white glow; the exceptions are those diamonds which show a yellow glow under
UV and show a similar glow under X-rays but this is not always so.
Michael O’Donoghue, Gems, Sixth Edition (2006)
Crystallography of Diamond
Crystal SystemIsometric
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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HabitMainly octahedrons, also cubes, rhombic dodecahedrons, twins, plates.
Walter Schumann, Gemstones of the world (2001)
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Geological Environment
Where found:It is known to be the product of the deep-seated crystallization of ultrabasic igneous magmas which have intruded as dikes or pipes of kimberlite or lamproite
Michael O’Donoghue, Gems, Sixth Edition (2006)
Inclusions in Diamond
Inclusions: olivine, garnet, diopside, graphite, tension and cleavage cracks, growth zoning, twinning lamellaes - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 31
Further Information
Mineral information:Diamond information at mindat.org
Significant Gem Localities
Angola
 
  • Lunda Norte Province
    • Cambulo City Council
      • Calonda
Khar'kiv et al. (1992)
Khar'kiv et al. (1992)
  • Lunda Sul Province
    • Catoca kimberlite field
Levinson et al. (1992)
Australia
 
  • New South Wales
    • Murchison Co.
Barron et al. (1996)
  • Northern Territory
    • Roper Gulf Region
      • Borroloola
gemexplorer.org
  • Western Australia
    • Derby-West Kimberley Shire
      • Ellendale
Jaques (1994)
Jaques (1994)
Jaques (1994)
    • Wyndham-East Kimberley Shire
      • Lake Argyle area
Chapman et al. (1996), Gemexplorer.org
Botswana
 
  • Central District
    • Letlhakane
Levinson et al. (1992)
    • Orapa
Levinson et al. (1992)
  • Southern District
    • Ngwaketse North District
      • Kanye
Levinson et al. (1992)
Brazil
 
  • Mato Grosso
    • Alto Rio Paraguai district
      • Nortelândia
        • Santana river
Cassedanne (1989)
Cassedanne (1989)
    • Juína
      • Sorriso river
Cassedanne (1989)
  • Minas Gerais
Cassedanne (1989)
    • Datas
Cassedanne (1989)
    • Diamantina
Cassedanne (1989)
      • São João da Chapada
Cassedanne (1989)
N. Haralyi (1998)
    • São Gonaçalo do Abaeté
Cassedanne (1989)
Canada
 
  • Northwest Territories
    • Lac de Gras
gemexplorer.org
Pell (1994)
Central African Republic
 
  • Mambéré-Kadéï Prefecture
Censier and Tourenq (1995)
China
 
  • Hunan Province
    • Changde Prefecture
      • Taoyuan Co.
R. Li (1999)
  • Liaoning Province (Manchuria; Dongbei Region)
    • Liaodong Peninsula
      • Dalian Prefecture
        • Wafangdian Co.
          • Fuxian kimberlite field
            • Laotiangou
Janse (1995)
            • Toudaogou (incl. Pipes No. 51; 68 & 74)
Janse (1995)
Janse (1995)
            • Wafangdian
Janse (1995)
  • Shandong Province
    • Linyi Prefecture
      • Yimeng Mts (Yimeng Shan)
        • Mengyin Co.
          • Mengyin Kimberlite field
            • Changma Kimberlite belt
Dobbs et al. (1994)
Democratic Republic of Congo (Zaïre)
 
  • Kasaï-Oriental
    • Mbuji Mayi (Bakwanga)
Janse (1995)
  • Kasaï (Kasaï-Occidental)
Janse (1995)
Ghana
 
  • Eastern Region
    • Birim diamond field
Levinson et al. (1992)
  • Western Region
    • Bogoso
Levinson et al. (1992)
Guinea
 
  • Kankan Region
    • Kérouané Prefecture
      • Gbenko
A. Janse (1999)
Guyana
 
  • Cuyuni-Mazaruni Region
    • Imbaimadai
Levinson et al. (1992)
  • Potaro-Siparuni Region
    • Kangaruma District
      • Potaro River
Levinson et al. (1992)
India
 
  • Andhra Pradesh
    • Hyderabad District
      • Golconda
gemexplorer.org
  • Madhya Pradesh
    • Panna District
      • Panna
Chatterjee and Rao (1995)
Indonesia
 
  • Kalimantan (Borneo)
    • Kalimantan Selatan Province (South Kalimantan Province)
      • Riam Kanan
gemexplorer.org
Janse and Sheahan (1995)
    • Kalimantan Tengah Province (Central Kalimantan Province)
Janse and Sheahan (1995)
Ivory Coast (Côte d'Ivoire)
 
  • Vallée du Bandama region
    • Katiola department
Janse (1996)
Lesotho
 
  • Mokhotlong District
    • Maluti Mts.
gemexplorer.org
Mali
 
  • Kayes Region
Janse (1996)
Myanmar
 
  • Kachin State
    • Myitkyina District
U Hlaing (1999)
Kammerling et al. (1994)
  • Shan State
    • Kyaukme District
      • Momeik Township
Hlaing (1990)
  • Tanintharyi Region (Tanintharyi Division; Taninthayi Division; Tenasserim Division)
    • Myeik District
Hlaing (1990)
Namibia
 
  • Karas Region
    • Lüderitz District
Gurney et al. (1991)
    • Orange River mining area
Janse (1995)
Janse (1995)
Russia
 
  • Eastern-Siberian Region
    • Krasnoyarsk Territory (Krasnoyarsk Kray; Krasnoyarskii Krai)
      • Anabarskii massif
        • Popigai river
Russian gemstones encyclopedia, V. V. Bukanov, 2006, p. 36
    • Sakha Republic (Saha Republic; Yakutia)
      • Daldyn-Alakit kimberlite field
Levinson et al. (1992)
Levinson et al. (1992)
Levinson et al. (1992)
Duval et al. (1996)
        • Daldyn
Duval et al. (1996)
Duval et al. (1996)
      • Mirny
Duval et al. (1996)
Duval et al. (1996)
      • Nakyn kimberlite field (Nakynsky kimberlite field)
        • Sredne-Markhinsky region
A. Janse (1999)
A. Janse (1999)
Levinson et al. (1992)
  • Northern Region
    • Arkhangel'skaja Oblast'
      • Zimny Bereg District
        • Zimny Bereg kimberlite field
Possoukhova et al. (1999)
          • Zolotitsa occurrence
Smirnov (1993)
33rd International Geological Congress (2008) session AAA-11 Metallogeny of the Arctic region: Diamondiferous kimberlites of the East Eurorean Platform: Specific features; Smirnov (1993)
Smirnov (1993)
Sierra Leone
 
  • Eastern Province
    • Kenema District
A. Janse (1999)
    • Kono District
gemexplorer.org
  • Northern Province
Levinson et al. (1992)
South Africa
 
  • Free State Province
    • Lejweleputswa District
      • Theunissen
        • Theunissen kimberlite field
A. Janse (1999)
    • Xhariep District
      • Koffiefontein
Janse (1995, 1996)
  • Gauteng Province
    • Pretoria District (Tshwane District)
      • Cullinan
Janse (1995, 1996)
  • Limpopo Province
    • Bushveld Complex
      • Waterberg District
        • Mokopane (Potgietersrus)
Janse (1995, 1996)
    • Capricorn District
      • Swartwater
        • Marnitz kimberlite cluster
Janse (1995, 1996)
    • Vhembe District
Janse (1995, 1996)
  • Northern Cape Province
    • Francis Baard District
      • Kimberley
Janse (1995, 1996)
Janse (1995, 1996)
Janse (1995, 1996)
Janse (1995, 1996)
      • Windsorton
        • Mount Rupert
Janse (1995, 1996)
    • Namakwa District (Namaqualand)
      • Gordonia District
        • Lime Acres
Janse (1995, 1996)
      • Kleinzee
Gurney et al. (1991)
Tanzania
 
  • Ruvuma Region
    • Tunduru District
gemexplorer.org
  • Shinyanga Region
    • Mwadui
Dirlam et al. (1992)
USA
 
  • Arkansas
    • Pike Co.
Pell (1994)
  • Colorado
    • Larimer Co.
      • State Line Kimberlite District
Johnson and Koivula (1996)
Venezuela
 
  • Bolívar
Coenraads et al. (1994)
      • Quebrada Grande River
Coenraads et al. (1994)
Zimbabwe
 
  • Manicaland
    • Mutare District (Umtali District)
      • Chiadzwa
gemexplorer.org
  • Matabeleland South
    • Beitbridge District
Duval et al. (1996)
  • Midlands
    • Zvishavane District
      • Zvishavane (Shabani; Shabanie; Shavani)
gemexplorer.org
Copyright © Jolyon & Katya Ralph 1993-2017. Site Map. Locality, gem & photograph data are the copyright of the individuals who submitted them. For more information please contact the . Gemdat.org is an online information resource dedicated to providing free gemmological information to all.