Prasiolite

Big Photo

Brazil
8.48 carats
© Rarestone.com

Prasiolite (Greek - leek-green stone) is a rare stone in nature. It can be produced artificially from violet amethyst or yellowish quartz by a combination of heat treatment and cobalt-60 or E-beam Gamma irradiation.

In sunlight, the colour commonly fades.

Prasiolite Gemstones by Colour

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

Prasiolite Gemstones by Size

This table shows distribution of Prasiolite 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:1.10 cts
Heaviest:24.09 cts
Average:10.91 cts
Total photos:41
Do you have a larger Prasiolite? Why not upload a photo?
1.10ct to 3.40ct3.40ct to 5.70ct5.70ct to 8.00ct8.00ct to 10.30ct10.30ct to 12.60ct12.60ct to 14.89ct14.89ct to 17.19ct17.19ct to 19.49ct19.49ct to 21.79ct21.79ct to 24.09ct
General Information
A variety or type of:Quartz
Other Names/Trade Names:
Chemical Formula
SiO
 
2
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Photos of natural/un-cut material from mindat.org
Prasiolite Treatments
Color produced by heat-treatment and irradiation of light amethyst: may fade with long exposure to sunlight - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 7
Physical Properties of Prasiolite
Mohs Hardness7
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Specific Gravity2.65
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
TenacityBrittle
Walter Schumann, Gemstones of the world (2001) Very brittle
Cleavage QualityNone
Walter Schumann, Gemstones of the world (2001)
FractureConchoidal
Walter Schumann, Gemstones of the world (2001)
Light SensitivityMay fade with long exposure to sunlight.
Walter Schumann, Gemstones of the world (2001)
Optical Properties of Prasiolite
Refractive Index1.544 to 1.553
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical CharacterUniaxial/+
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Birefringence0.009
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
PleochroismVery weak: light green - pale green
Walter Schumann, Gemstones of the world (2001)
Dispersion0.013
Walter Schumann, Gemstones of the world (2001)
Colour
Colour (General)Leek-green
Walter Schumann, Gemstones of the world (2001)
More from other references
Causes of ColourGreen, Fe2+.
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyTransparent,Translucent,Opaque
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Fluorescence & other light emissions
Fluorescence (General)None
Walter Schumann, Gemstones of the world (2001)
Crystallography of Prasiolite
Crystal SystemTrigonal
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
HabitHexagonal prisms
Walter Schumann, Gemstones of the world (2001)
Further Information
Mineral information:Prasiolite information at mindat.org
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