Topaz
Physical Properties
| Color | orange |
| Form/Habit | massive |
| Lusture | vitreous |
| Streak | white |
| Hardness | 8 |
| Cleavage | perfect 1 set basal |
| Fracture | sub conchoidal |
| Specific Gravity | 3.5-3.6 (moderate) |
| Chemical Composition | Al2SiO4(OH, F)2 |
| Crystal System | orthorhombic |
| Diagnostic Properties | hardness of 8, perfect 1 set basal cleavage, sub conchoidal fractures |