![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/9/9a/Several_corundum_crystals.jpg/640px-Several_corundum_crystals.jpg&w=640&q=50)
කුරුවින්ද
From Wikipedia, the free encyclopedia
Quick Facts කුරුවින්ද, General ...
කුරුවින්ද | |
---|---|
![]() | |
General | |
Category | Oxide mineral – Hematite group |
රසායනික සූත්රය | Aluminium oxide, Al2O3 |
Strunz classification | 04.CB.05 |
Dana classification | 4.3.1.1 |
Crystal symmetry | Trigonal (32/m) |
Unit cell | a = 4.75 Å, c = 12.982 Å; Z=6 |
Identification | |
පාට / පැහැය | Colorless, gray, brown; pink to pigeon-blood-red, orange, yellow, green, blue to cornflower blue, violet; may be color zoned, asteriated mainly grey and brown |
Crystal habit | Steep bipyramidal, tabular, prismatic, rhombohedral crystals, massive or granular |
Crystal system | Trigonal (Hexagonal Scalenohedral) Symbol (32/m) Space group: R3c |
Twinning | Polysynthetic twinning common |
Cleavage | None – parting in 3 directions |
Fracture | Conchoidal to uneven |
Mohs scale hardness | 9 (defining mineral)[1] |
Luster | Adamantine to vitreous |
Streak | White |
Diaphaneity | Transparent, translucent to opaque |
Specific gravity | 3.95–4.10 |
Optical properties | Uniaxial (–) |
Refractive index | nω = 1.767–1.772 nε = 1.759–1.763 |
Pleochroism | None |
Melting point | 2044 °C |
Fusibility | Infusible |
Solubility | Insoluble |
Alters to | May alter to mica on surfaces causing a decrease in hardness |
Other characteristics | May fluoresce or phosphoresce under UV |
References | [2][3][4][5] |
Major varieties | |
Sapphire | Any color except red |
Ruby | Red |
Emery | Black granular corundum intimately mixed with magnetite, hematite, or hercynite |
Close