Afghanistan
.22 carats
© raregemhunter
General Information | ||||||
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Chemical Formula |
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Photos of natural/un-cut material from mindat.org | ||||||
Physical Properties of Brookite | ||||||
Mohs Hardness | 5.5 to 6Gemmological Tables (2004) , More from other references | |||||
Specific Gravity | 3.87 to 4.14Gemmological Tables (2004) , More from other references | |||||
Cleavage Quality | IndistinctGemstones (2009) , | |||||
Fracture | Sub-ConchoidalGemstones (2009) , | |||||
Optical Properties of Brookite | ||||||
Refractive Index | 2.583 to 2.741Gemmological Tables (2004) , More from other references | |||||
Optical Character | Biaxial/+Gemmological Tables (2004) , More from other references | |||||
Birefringence | 0.117 to 0.158Gemmological Tables (2004) , More from other references | |||||
Pleochroism | NilGemstones (2009) , | |||||
Dispersion | StrongGemstones (2009) , | |||||
Colour | ||||||
Colour (General) | Yellowish-brown, red-brown, blackGemmological Tables (2004) , More from other references | |||||
Transparency | OpaqueGemmological Tables (2004) , More from other references | |||||
Lustre | Adamantine,MetallicGems, Sixth Edition (2006) , More from other references | |||||
Crystallography of Brookite | ||||||
Crystal System | OrthorhombicGemmological Tables (2004) , More from other references | |||||
Habit | Varied habitGems, Sixth Edition (2006) , More from other references | |||||
Geological Environment | ||||||
Where found: | Occurs in granite, porphyry, greiss, chlorite and mica schists.Gemstones (2009) , | |||||
Further Information | ||||||
Mineral information: | Brookite information at mindat.org |