Name | CORUNDUM | Variety | SAPPHIRE | Origin | Ratnapura (Sri Lanka) | Hardness | 9 | Composition | Al2O3 | Crystaline sys. | TRIGONAL
| Size | 7,5 x 3 x 2,5 cm | Weight | 58 gr |
Description:
Corundum was chosen by the geologist Friedrich Mohs to represent grade 9 in his famous scale first published in 1825 and which is still valid today. It is second hardest material on Earth. Corundum crystals usually appear alone. Real crystal twins (except for synthetic ones) are extremely rare, as is the case with this specimen. |
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CORUNDUM
VARIETY SAPPHIRE
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