රතුකැට
| රතුකැට | |
|---|---|
 Natural ruby crystals from Winza, Tanzania | |
| General | |
| Category | Mineral variety |
| රසායනික සූත්රය | aluminium oxide with chromium, Al2O3:Cr |
| Identification | |
| පාට / පැහැය | Red, may be brownish, purplish or pinkish |
| Crystal habit | Varies with locality. Terminated tabular hexagonal prisms. |
| Crystal system | Trigonal (Hexagonal Scalenohedral) Symbol (−3 2/m) Space Group: R-3c |
| Cleavage | No true cleavage |
| Fracture | Uneven or conchoidal |
| Mohs scale hardness | 9.0 |
| Luster | Vitreous |
| Streak | white |
| Diaphaneity | transparent |
| Specific gravity | 4.0 |
| Refractive index | nω=1.768 – 1.772 nε=1.760 – 1.763, Birefringence 0.008 |
| Pleochroism | Orangey red, purplish red |
| Ultraviolet fluorescence | red under longwave |
| Melting point | 2044 °C |
| Solubility | none |
| Major varieties | |
| Sapphire | Any color except shades of red |
| Corundum | various colors |
| Emery | Granular |