දඹ පළිඟු
| දඹ පළිඟු | |
|---|---|
| ගොනුව:දඹ පළිඟු. Magaliesburg, South Africa.jpg Amethyst cluster from Magaliesburg, South Africa. | |
| General | |
| Category | Mineral variety |
| රසායනික සූත්රය | සිලිකා (silicon dioxide, SiO2) |
| Identification | |
| පාට / පැහැය | දම් පාට |
| Crystal habit | 6-sided prism ending in 6-sided pyramid (typical) |
| Crystal system | rhombohedral class 32 |
| Twinning | Dauphine law, Brazil law, and Japan law |
| Cleavage | නැත |
| Fracture | Conchoidal |
| Mohs scale hardness | 7–lower in impure varieties |
| Luster | Vitreous/glossy |
| Streak | සුදු |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 2.65 constant; variable in impure varieties |
| Optical properties | Uniaxial (+) |
| Refractive index | nω = 1.543–1.553 nε = 1.552–1.554 |
| Birefringence | +0.009 (B-G interval) |
| Pleochroism | නැත |
| Melting point | 1650±75 °C |
| Solubility | insoluble in common solvents |
| Other characteristics | Piezoelectric |
