Difference between revisions of "Template:Topaz"
From The Gemology Project
m |
(Added "plane" to basal) |
||
Line 9: | Line 9: | ||
| Habit || Prismatic with pyramidal/domed terminations | | Habit || Prismatic with pyramidal/domed terminations | ||
|- | |- | ||
− | | Cleavage || Perfect, basal | + | | Cleavage || Perfect, basal plane |
|- | |- | ||
| Fracture || Sub-conchoidal to uneven | | Fracture || Sub-conchoidal to uneven |
Latest revision as of 19:46, 9 February 2007
Topaz | |
---|---|
Chemical composition | Al2(F,OH)2SiO4 |
Crystal system | Orthorhombic |
Habit | Prismatic with pyramidal/domed terminations |
Cleavage | Perfect, basal plane |
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) |