Dioptase

Big Photo

DR Congo
3.44 carats
© Mineral Classics

Dioptase is named after Greek word for "view through" referring to the mineral's two cleavage directions that are visible inside unbroken crystals.

Dioptase is a popular collectors' mineral specimen and is smetimes cut into small emerald-like gems. The material is very soft to be worn as a ring-stone, but small specimens are sometimes mounted in pendants and brooches.

Dioptase Gemstones by Colour

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

Dioptase Gemstones by Size

This table shows distribution of Dioptase 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:0.18 cts
Heaviest:3.66 cts
Average:1.51 cts
Total photos:12
Do you have a larger Dioptase? Why not upload a photo?
0.18ct to 0.53ct0.53ct to 0.88ct0.88ct to 1.22ct1.22ct to 1.57ct1.57ct to 1.92ct1.92ct to 2.27ct2.27ct to 2.62ct2.62ct to 2.96ct2.96ct to 3.31ct3.31ct to 3.66ct
General Information
Chemical Formula
CuSiO
 
2
(OH)
 
2
Michael O’Donoghue, Gems, Sixth Edition (2006)
More from other references
Photos of natural/un-cut material from mindat.org
Physical Properties of Dioptase
Mohs Hardness5
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Specific Gravity3.25 to 3.35
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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TenacityBrittle
Walter Schumann, Gemstones of the world (2001)
Cleavage QualityPerfect
Walter Schumann, Gemstones of the world (2001)
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FractureConchoidal
Walter Schumann, Gemstones of the world (2001)
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Optical Properties of Dioptase
Refractive Index1.644 to 1.720
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Optical CharacterUniaxial/+
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Birefringence0.051 to 0.053
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) DoublingMore from other references
PleochroismWeak; dark emerald green, light emerald green.
Walter Schumann, Gemstones of the world (2001)
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Dispersion0.036
Walter Schumann, Gemstones of the world (2001)
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Colour
Colour (General)Dark vivid bluish-green
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Causes of ColourGreen, Cu2+ in octahedral coordination
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyTranslucent
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Usually translucentMore from other references
LustreVitreous
Arthur Thomas, Gemstones (2009)
Fluorescence & other light emissions
Fluorescence (General)None
Walter Schumann, Gemstones of the world (2001)
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Crystallography of Dioptase
Crystal SystemTrigonal
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
HabitPrismatic or rhombohedral crystals
Michael O’Donoghue, Gems, Sixth Edition (2006)
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Geological Environment
Where found:Dioptase is found in the oxidized zones of some copper deposits.
Michael O’Donoghue, Gems, Sixth Edition (2006)
Further Information
Mineral information:Dioptase information at mindat.org
Significant Gem Localities
Kazakhstan
 
  • Karaganda
    • Bukhar-Zhyrau
      • Altyn-Tyube area
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 405
Namibia
 
  • Oshikoto Region
    • Tsumeb
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 406
Republic of Congo (Brazzaville)
 
  • Pool Department
    • Kindanba District
      • Renéville
        • Renéville Mine (Djoué Mines)
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 405
    • Mindouli District
      • Mindouli
        • Pimbi hill
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 406
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