| නිල් මැණික් නිල්කැට | |
|---|---|
 The 423-carat (85 g) blue Logan sapphire | |
| General | |
| Category | Oxide mineral |
| රසායනික සූත්රය | aluminium oxide, Al2O3 |
| Identification | |
| පාට / පැහැය | නිල් |
| Crystal habit | massive and granular |
| Crystal system | Trigonal Symbol (32/m) Space Group: R3c |
| Cleavage | none |
| Fracture | conchoidal, splintery |
| Mohs scale hardness | 9.0 |
| Luster | vitreous |
| Streak | white |
| Specific gravity | 3.95–4.03 |
| Optical properties | Abbe number 72.2 |
| Refractive index | nω=1.768–1.772 nε=1.760–1.763, Birefringence 0.008 |
| Pleochroism | Strong |
| Melting point | 2030–2050 °C |
| Fusibility | infusible |
| Solubility | Insoluble |
| Other characteristics | coefficient of thermal expansion (5.0–6.6)×10−6/K |
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