Chrysoprase

Big Photo

India
6.86 carats
© gemselect.com

Chrysoprase is an attractive apple-green form of Chalcedony that is coloured by nickel. One of the most prized forms of Chalcedony.

Colour can fade in sunlight and when heated, colours may recover under moist storage.

Used as cabochons, for necklaces, and for ornamental objects. In earlier centuries, it was used as a luxurious decorative stone for interior decorations.

Chrysoprase Gemstones by Colour

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

Chrysoprase Gemstones by Size

This table shows distribution of Chrysoprase 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:0.17 cts
Heaviest:51.98 cts
Average:10.72 cts
Total photos:28
Do you have a larger Chrysoprase? Why not upload a photo?
0.17ct to 5.35ct5.35ct to 10.53ct10.53ct to 15.71ct15.71ct to 20.89ct20.89ct to 26.08ct26.08ct to 31.26ct31.26ct to 36.44ct36.44ct to 41.62ct41.62ct to 46.80ct46.80ct to 51.98ct
General Information
A variety or type of:Chalcedony, which is a variety of Quartz
Chemical Formula
SiO
 
2
Walter Schumann, Gemstones of the world (2001)
Photos of natural/un-cut material from mindat.org
Chrysoprase Treatments
Dyed green (chromium) - chelsea: pinkish to reddish. Might be dyed with nickel-rich solution: standard tests limited - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 7
Physical Properties of Chrysoprase
Mohs Hardness6.5 to 7
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Specific Gravity2.58 to 2.64
Walter Schumann, Gemstones of the world (2001)
More from other references
TenacityBrittle
Walter Schumann, Gemstones of the world (2001)
Cleavage QualityNone
Walter Schumann, Gemstones of the world (2001)
Optical Properties of Chrysoprase
Refractive Index1.530 to 1.543
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical CharacterUniaxial/+
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Birefringenceup to to 0.004
Walter Schumann, Gemstones of the world (2001)
PleochroismAbsent
Walter Schumann, Gemstones of the world (2001)
DispersionNone
Walter Schumann, Gemstones of the world (2001)
Colour
Colour (General)Colored by nickel: (yellowish)-green
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Colour (Chelsea Filter)Greenish
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Causes of ColourGreen colour is caused by microscopic inclusions of silicates with Ni-bearing layers (willemseite, népouite, etc).
Gemdat.org, Management Team (2012)
More from other references
TransparencyTranslucent,Opaque
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
More from other references
Fluorescence & other light emissions
Fluorescence (General)None
Walter Schumann, Gemstones of the world (2001)
Crystallography of Chrysoprase
Crystal SystemTrigonal
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
HabitMicrocrystalline aggregates
Walter Schumann, Gemstones of the world (2001)
Geological Environment
Where found:It occurs in quartz veins in nickel-bearing rocks or in veins in laterites overlying Ni-bearing serpentinites
(Queensland) and associated with jadeite in veins in serpentinized gabbro and ultramafic inclusions (Lower Silesia.)
Michael O’Donoghue, Gems, Sixth Edition (2006)
Spectrographic Data
Calculated Spectra:
Click spectra for more information
Chrysoprase - Locality: Unknown
Further Information
Mineral information:Chrysoprase information at mindat.org
Significant Gem Localities
Myanmar
 
  • Mandalay Region (Mandalay Division)
    • Pyin-Oo-Lwin District
      • Mogok Township
        • Bernardmyo
          • Pyaung Gaung
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Poland
 
  • Lower Silesia (Dolnośląskie)
    • Ząbkowice District
Gemstones of the world, Walter Schumann (2001)
USA
 
  • California
    • Tulare Co.
      • Ivanhoe
        • Venice Hills
Tucker, W. Burling (1919), El Dorado, Lassen, Modoc, Tehama, and Tulare Counties: California Mining Bureau. Report 15: 911; MacFall (1951), Gem Hunter's Guide, 1st ed.; Goodwin, Joseph Grant (1958), Mines and mineral resources of Tulare County, California: California Journal of Mines and Geology (Report 54): 54(3): 344; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 318; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 350, 424.
      • Tennessee Knob
Kunz, George Frederick (1899), Precious stones: Mineral Resources U.S., 1898: 589; Tucker, W. Burling (1919), Tulare Counties: California Mining Bureau. Report 15: 911; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 318.
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.