Jasper

Big Photo

India
59.7 carats
© gemselect.com

Jasper is usually considered as Chalcedony; sometimes, however, scientists put it in a group by itself within the quartz group because of its grainy structure.

The name jasper is derived from the Greek and means "spotted stone".

The finely grained, dense jasper contains up to 20 percent foreign materials, which determine its colour, streak, and appearance. Uniformly colored jasper is rare, usually it is multicolored, striped, or flamed. Sometimes jasper can be grown together with agate or opal. There is also some fossilized material.

Jasper Gemstones by Colour

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

Jasper Gemstones by Size

This table shows distribution of Jasper 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:10.73 cts
Heaviest:81.30 cts
Average:40.34 cts
Total photos:63
Do you have a larger Jasper? Why not upload a photo?
10.73ct to 17.79ct17.79ct to 24.84ct24.84ct to 31.90ct31.90ct to 38.96ct38.96ct to 46.02ct46.02ct to 53.07ct53.07ct to 60.13ct60.13ct to 67.19ct67.19ct to 74.24ct74.24ct to 81.30ct
General Information
A variety or type of:Chalcedony, which is a variety of Quartz
Varieties/Types:
Dallasite - A variety of Jasper from Vancouver Island, British Columbia, Canada.
Orbicular Jasper - Jasper containing numerous spherical inclusions.
Chemical Formula
SiO
 
2
Walter Schumann, Gemstones of the world (2001)
Photos of natural/un-cut material from mindat.org
Jasper Treatments
Dyed blue to imitate lapis, "Swiss lapis": lack of pyrite inclusion, chelsea - greenish-blue to red - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 7
Physical Properties of Jasper
Mohs Hardness6.5 to 7
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Specific Gravity2.58 to 2.91
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Cleavage QualityNone
Walter Schumann, Gemstones of the world (2001)
FractureConchoidal,Splintery
Walter Schumann, Gemstones of the world (2001)
Optical Properties of Jasper
Refractive Index1.540 (+/-)
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Optical CharacterUniaxial/+
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
BirefringenceNone
Walter Schumann, Gemstones of the world (2001)
More from other references
PleochroismAbsent
Walter Schumann, Gemstones of the world (2001)
DispersionNone
Walter Schumann, Gemstones of the world (2001)
Colour
Colour (General)All colors, mostly striped or spotted.
Walter Schumann, Gemstones of the world (2001)
More from other references
Causes of ColourOrange to red, submicroscopic to microscopic inclusions of hydrous Fe oxides
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyOpaque
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Fluorescence & other light emissions
Fluorescence (General)None
Walter Schumann, Gemstones of the world (2001)
Crystallography of Jasper
Crystal SystemTrigonal
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
HabitMicrocrystalline aggregate
Walter Schumann, Gemstones of the world (2001)
Geological Environment
Where found:Occurs as extensive beds of sedimentary or metamorphic origin. Jasper occurs as a cavity filling or as nodules or veins in iron ores. It occurs in altered igneous rocks and in detrital deposits. It may occur in variegated red to brown colours as a petrifying agent of wood.
Michael O’Donoghue, Gems, Sixth Edition (2006)
Further Information
Mineral information:Jasper information at mindat.org
Significant Gem Localities
Czech Republic
 
  • Bohemia (Böhmen; Boehmen)
    • Hradec Králové Region
      • Jičín (Jitschin; Gitschin)
No reference listed
Madagascar
 
  • Mahajanga Province (Majunga)
    • Sofia Region
      • Analalava District
        • Ambolobozo
mindat.org
Morocco
 
  • Meknès-Tafilalet Region
    • Khénifra Province
      • Midelt
        • Upper Moulouya lead district
mindat.org
Netherlands
 
  • Gelderland
mindat.org
Peru
 
  • Huánuco Department
  • Lima Department
    • Cañete Province
  • Puno Department
Portugal
 
  • Beja District
    • Mértola
      • Alcaria Ruiva
mindat.org
Russia
 
  • Urals Region
    • Southern Urals
      • Orenburgskaya Oblast'
        • Orsk
Занимательная минералогия, Ферсман А., 1953, стр. 50
USA
 
  • California
    • Inyo Co.
      • Amargosa Range
        • Black Mts
          • Jubilee Pass
Symons, Henry Heilbronner (1940), Quartz gem stones of California: Rocks & Minerals: 15: 41; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 317.
    • Santa Clara Co.
      • Santa Cruz Mts
        • Paradise Valley
[var: Orbicular Jasper] Melhase, John (1934), A diversity of many fine minerals available in California for collectors: Oregon Mineralogist: 2(7): 7; Mineralogist, The (1935): 3(3): 34; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 318; www.cst.cmich.edu/users/dietr1rv/jasper.htm
    • Siskiyou Co.
      • Klamath Mts
        • Cinnabar Camp
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
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