Carnelian

Big Photo

Mozambique
3.84 carats
© Brian Kosnar - Mineral Classics

Carnelian is probably named after the colour of the kornel cherry because of its colour. It is brownish red to orange, translucent to opaque Chalcedony variety. In some cases portions of the stone are paler than others, and specimens with a pale central portion passing gradually into a dark coloured exterior are not uncommon.

Many stones, which in the natural condition are of a dirty yellow colour and unsuitable for gems, on being heated acquire the fine carnelian colour, and with it a considerable increase in value.

When held against the light, the colour variety shows stripes, natural carnelian shows a cloudy distribution of colour.

Carnelian Gemstones by Colour

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

Carnelian Gemstones by Size

This table shows distribution of Carnelian 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:0.84 cts
Heaviest:120 cts
Average:10.92 cts
Total photos:40
Do you have a larger Carnelian? Why not upload a photo?
0.84ct to 12.76ct12.76ct to 24.67ct24.67ct to 36.59ct36.59ct to 48.50ct48.50ct to 60.42ct60.42ct to 72.34ct72.34ct to 84.25ct84.25ct to 96.17ct96.17ct to 108.08ct108.08ct to 120.00ct
General Information
A variety or type of:Chalcedony, which is a variety of Quartz
Other Names/Trade Names:
Chemical Formula
SiO
 
2
Gemdat.org, Management Team (2012)
Photos of natural/un-cut material from mindat.org
Carnelian Treatments
The colour can be enhanced by heating. - Gemstones of the world, Walter Schumann, 2001, p 126
Carnelian Simulants
Most carnelians offered today are agates which are dyed and then heat-treated. - Gemstones of the world, Walter Schumann, 2001, p 126
Physical Properties of Carnelian
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
Cleavage QualityNone
Walter Schumann, Gemstones of the world (2001)
FractureUneven
Walter Schumann, Gemstones of the world (2001)
Optical Properties of Carnelian
Refractive Index1.535 to 1.539
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical CharacterUniaxial/+
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Birefringence0.003 to 0.009
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
PleochroismAbsent
Walter Schumann, Gemstones of the world (2001)
DispersionNone
Walter Schumann, Gemstones of the world (2001)
Colour
Colour (General)Red, orange, reddish
Gemdat.org, Management Team (2012)
Causes of ColourOrange to red, submicroscopic to microscopic inclusions of hydrous Fe oxides
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyTranslucent,Opaque
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Semi-transparent to opaque
LustreWaxy,Resinous
Arthur Thomas, Gemstones (2009)
Fluorescence & other light emissions
Fluorescence (General)Blue-white
Walter Schumann, Gemstones of the world (2001)
Crystallography of Carnelian
Crystal SystemTrigonal
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
HabitFibrous to grained aggregate
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Further Information
Mineral information:Carnelian information at mindat.org
Significant Gem Localities
Peru
 
  • Huancavelica Department
    • Huancavelica Province
      • Ascencion District
        • Yauricocha Parish
Sri Lanka
 
  • Sabaragamuwa Province
    • Ratnapura District
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.