Brookite is a mineral whose composition is similar to that of other minerals: anatase and rutile. When the temperature rises above 750 degrees Celsius, brookite turns into rutile.
You can see brookite stone for sale and buy it in the Minerals of Russia online store.
General | |
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Category | Oxide minerals |
Formula (repeating unit) |
TiO2 |
Strunz classification | 4.DD.10 (10 ed) 4/D.15-10 (8 ed) |
Dana classification | 4.4.5.1 |
Crystal system | Orthorhombic |
Crystal class | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
Space group | Pbca |
Unit cell | a = 5.4558 Å, b = 9.1819 Å, c = 5.1429 Å; Z = 8 |
Identification | |
Formula mass | 79.88 g/mol |
Color | Deep red, reddish brown, yellowish brown, brown, or black |
Crystal habit | Tabular and striated, pyramidal or pseudohexagonal |
Twinning | On {120}, uncertain |
Cleavage | Poor on {120}, in traces on {001} |
Fracture | Subconchoidal to irregular |
Tenacity | Brittle |
Mohs scale hardness | 5+1⁄2 to 6 |
Luster | Submetallic |
Streak | White, greyish or yellowish |
Diaphaneity | Opaque to translucent |
Specific gravity | 4.08 to 4.18 |
Optical properties | Biaxial (+) |
Refractive index | nα = 2.583 nβ = 2.584 nγ = 2.700 |
Birefringence | δ = 0.117 |
Pleochroism | Very weak, yellowish, reddish, orange to brown |
2V angle | Calculated: 12° to 20° |
Dispersion | 0.131 (compare to diamond at 0.044) |
Ultraviolet fluorescence | Non-fluorescent |