Crocoite

Big Photo

Tasmania, Australia
4.20 carats
© Rarestone.com

Crocoite was named crocoise in 1832, from the Greek "krokos" - saffron, in allusion to its colour. The name was first altered to crocoisite and afterwards to crocoite. It was discovered at Berezovsky deposit near Ekaterinburg in the Urals in 1766.

Crocoite is commonly found as well-developed crystals of a bright hyacinth-red, orange, or yellow colour, near transparent to translucent, and have an adamantine to vitreous lustre.

The material is brittle, has good cleavage and very sensitive to heat. Transparent crystals of crocoite have been faceted into brilliant stones for collectors.

Crocoite Gemstones by Colour

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

Crocoite Gemstones by Size

This table shows distribution of Crocoite 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:1.13 cts
Heaviest:4.20 cts
Average:3.14 cts
Total photos:3
Do you have a larger Crocoite? Why not upload a photo?
1.13ct to 1.44ct1.44ct to 1.74ct1.74ct to 2.05ct2.05ct to 2.36ct2.36ct to 2.67ct2.67ct to 2.97ct2.97ct to 3.28ct3.28ct to 3.59ct3.59ct to 3.89ct3.89ct to 4.20ct
General Information
Chemical Formula
PbCrO
 
4
Michael O’Donoghue, Gems, Sixth Edition (2006)
More from other references
Photos of natural/un-cut material from mindat.org
Physical Properties of Crocoite
Mohs Hardness2.5 to 3
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Specific Gravity5.90 to 6.10
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Cleavage QualityDistinct
Arthur Thomas, Gemstones (2009)
FractureConchoidal
Arthur Thomas, Gemstones (2009)
Optical Properties of Crocoite
Refractive Index2.31 to 2.66
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Optical CharacterBiaxial/+
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Birefringence0.35
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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PleochroismDistinctly trichroic
Arthur Thomas, Gemstones (2009)
DispersionNil
Arthur Thomas, Gemstones (2009)
Colour
Colour (General)Yellowish-red, orange
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Causes of ColourYellow to red, O2-Cr6+ charge transfer
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyTransparent,Translucent
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
More from other references
LustreAdamantine,Vitreous
Arthur Thomas, Gemstones (2009)
Fluorescence & other light emissions
Fluorescence (General)A reddish to dark-brown fluorescence may sometimes be seen
Michael O’Donoghue, Gems, Sixth Edition (2006)
Crystallography of Crocoite
Crystal SystemMonoclinic
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
More from other references
HabitPrismatic
Michael O’Donoghue, Gems, Sixth Edition (2006)
More from other references
Geological Environment
Where found:It is found in the oxidized zone of lead deposits in association with chromium-bearing rocks.
Michael O’Donoghue, Gems, Sixth Edition (2006)
Further Information
Mineral information:Crocoite information at mindat.org
Significant Gem Localities
Australia
 
  • Tasmania
    • West Coast municipality
      • Zeehan District
        • Dundas mineral field
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 402
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 402
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