Labradorite
Madagascar
9.6 carats
© gemselect.com
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.
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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?
| General Information | |||||||||||||||||||||
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| 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 |
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| Photos of natural/un-cut material from mindat.org | |||||||||||||||||||||
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| Physical Properties of Labradorite | |||||||||||||||||||||
| Mohs Hardness | 6 to 6.5, Blue Chart Gem Identification (2010) More from other references | ||||||||||||||||||||
| Specific Gravity | 2.69 to 2.72, Blue Chart Gem Identification (2010) More from other references | ||||||||||||||||||||
| Tenacity | Brittle, Gems, Sixth Edition (2006) | ||||||||||||||||||||
| Cleavage Quality | Perfect, Gemmological Tables (2004) More from other references | ||||||||||||||||||||
| Fracture | Uneven, Gems, Sixth Edition (2006) | ||||||||||||||||||||
| Optical Properties of Labradorite | |||||||||||||||||||||
| Refractive Index | 1.554 to 1.573, Blue Chart Gem Identification (2010) More from other references | ||||||||||||||||||||
| Optical Character | Biaxial/+, Blue Chart Gem Identification (2010) More from other references | ||||||||||||||||||||
| Birefringence | 0.007 to 0.011, Blue Chart Gem Identification (2010) More from other references | ||||||||||||||||||||
| Pleochroism | From the Congo, red stones show weak pleochroism whilst greenstones have distinct greenish yellow to bluish green pleochroism, Gems, Sixth Edition (2006) | ||||||||||||||||||||
| Dispersion | Low (0.012), Gems, Sixth Edition (2006) But the combination of a high polish and minute inclusions can simulate the effect of moderate dispersion | ||||||||||||||||||||
| Colour | |||||||||||||||||||||
| Colour (General) | Dark gray, black-gray, labradorescent: blue-green, golden yellow, purple, bronze colour, Gemmological Tables (2004) More from other references | ||||||||||||||||||||
| Causes of Colour | Multicolors, diffraction of light by the internal lamellar structure. Red (in the material from Oregon), submicroscopic metallic copper particles. Green and orange could be Cu+, Pragmatic Spectroscopy For Gemologists (2011) | ||||||||||||||||||||
| Transparency | Transparent,Translucent,Opaque, Gemstones of the world (2001) More from other references | ||||||||||||||||||||
| Lustre | Vitreous, Gems, Sixth Edition (2006) | ||||||||||||||||||||
| Fluorescence & other light emissions | |||||||||||||||||||||
| Fluorescence (Short Wave UV) | The intensity is diminished and fluorescence is a weak chalky pinkish orange, Gems, Sixth Edition (2006) | ||||||||||||||||||||
| Fluorescence (Long-Wave UV) | Red stones (Congo) fluoresced weak to distinct orange and greenstones (Congo) appeared distinctly orange, Gems, Sixth Edition (2006) | ||||||||||||||||||||
| Crystallography of Labradorite | |||||||||||||||||||||
| Crystal System | Triclinic, Blue Chart Gem Identification (2010) More from other references | ||||||||||||||||||||
| Habit | Platy, prismatic, Gemstones of the world (2001) More from other references | ||||||||||||||||||||
| Geological Environment | |||||||||||||||||||||
| Where found: | A common constituent of anorthosites, norites, basalts and gabbros as well as other igneous rocks. In the metamorphic environment it occurs in gneisses derived from basic rocks., Gems, Sixth Edition (2006) | ||||||||||||||||||||
| Inclusions in Labradorite | |||||||||||||||||||||
| Transparent stones: common elongated black inclusions (ilmenite) - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 6 Red hematite platelets, black magnetite needles, ilmenite - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 10 | |||||||||||||||||||||
| Further Information | |||||||||||||||||||||
| Mineral information: | Labradorite information at mindat.org | ||||||||||||||||||||
| Significant Gem Localities | |||||||||||||||||||||
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