Labradorite

Big Photo

Madagascar
9.6 carats
© gemselect.com

A type of feldspar consisting of between 30-50% Albite and 50-70% Anorthite.

Labradorite was named after peninsula of Labrador in Canada, where it was first found.

It shows labradorescence - a shiller effect in lustrous metallic tints, often blue and green, and sometimes the complete spectrum. This effect is caused by interference of light from lattice distortions resulting from alternating microscopic exsolution lamellae of high- and low-calcium plagioclase phases.

Labradorite Gemstones by Colour

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

Labradorite Gemstones by Size

This table shows distribution of Labradorite 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:2.53 cts
Heaviest:145.2 cts
Average:34.79 cts
Total photos:21
Do you have a larger Labradorite? Why not upload a photo?
2.53ct to 16.80ct16.80ct to 31.06ct31.06ct to 45.33ct45.33ct to 59.60ct59.60ct to 73.87ct73.87ct to 88.13ct88.13ct to 102.40ct102.40ct to 116.67ct116.67ct to 130.93ct130.93ct to 145.20ct
General Information
A variety or type of:Feldspar
Varieties/Types:
Spectrolite - Trade name for a Labradorite from Finland that shows the spectral colours especially effectively.
Chemical Formula
Na(30-50%)Ca(70-50%)(Al,Si)AlSi
 
2
O
 
8
Michael O’Donoghue, Gems, Sixth Edition (2006)
Physical Properties of Labradorite
Mohs Hardness6 to 6.5
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Specific Gravity2.69 to 2.72
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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TenacityBrittle
Michael O’Donoghue, Gems, Sixth Edition (2006)
Cleavage QualityPerfect
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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FractureUneven
Michael O’Donoghue, Gems, Sixth Edition (2006)
Refractive Index1.554 to 1.573
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Optical CharacterBiaxial/+
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Birefringence0.007 to 0.011
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
PleochroismFrom the Congo, red stones show weak pleochroism whilst greenstones have distinct greenish yellow to bluish green pleochroism
Michael O’Donoghue, Gems, Sixth Edition (2006)
Dispersion
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