Difference between revisions of "Template:Topaz"
From The Gemology Project
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| Chemical composition || Al<sub>2</sub>(F,OH)<sub>2</sub>SiO<sub>4</sub> | | Chemical composition || Al<sub>2</sub>(F,OH)<sub>2</sub>SiO<sub>4</sub> | ||
|- | |- | ||
− | | Crystal system || | + | | Crystal system || Orthorhombic |
|- | |- | ||
− | | Habit || | + | | Habit || Prismatic with pyramidal/domed terminations |
|- | |- | ||
− | | Cleavage || | + | | Cleavage || Perfect, basal |
|- | |- | ||
− | | Fracture || | + | | Fracture || Sub-conchoidal to uneven |
|- | |- | ||
| Hardness || 8 | | Hardness || 8 | ||
|- | |- | ||
− | | Optic nature || | + | | Optic nature || Biaxial + |
|- | |- | ||
| Refractive index || 1.606-1.644 | | Refractive index || 1.606-1.644 | ||
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| Birefringence || 0.008 - 0.010 | | Birefringence || 0.008 - 0.010 | ||
|- | |- | ||
− | | Dispersion || | + | | Dispersion || Low, 0.014 |
|- | |- | ||
| Specific gravity || 3.49 - 3.57 | | Specific gravity || 3.49 - 3.57 | ||
|- | |- | ||
− | | Lustre || | + | | Lustre || Vitreous |
|- | |- | ||
− | | Pleochroism || | + | | Pleochroism || Distinct to strong (depending on body color) |
|} | |} |
Revision as of 21:08, 23 December 2006
Topaz | |
---|---|
Chemical composition | Al2(F,OH)2SiO4 |
Crystal system | Orthorhombic |
Habit | Prismatic with pyramidal/domed terminations |
Cleavage | Perfect, basal |
Fracture | Sub-conchoidal to uneven |
Hardness | 8 |
Optic nature | Biaxial + |
Refractive index | 1.606-1.644 |
Birefringence | 0.008 - 0.010 |
Dispersion | Low, 0.014 |
Specific gravity | 3.49 - 3.57 |
Lustre | Vitreous |
Pleochroism | Distinct to strong (depending on body color) |