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Quartz
| Chemical Composition |
Silicon dioxide |
| Colour |
Very wide colour range -- colourless, yellow, brown, purple, pink, greenish. Crypto crystalline quartz often displays exotic colour bands, swirls, and other patterns. |
| Refractive Index |
R.I. 1.553-1.554. Uniaxial positive |
| Durability |
Hardness 7 |
| Crystal Structure |
Hexagonal |
| Specific Gravity |
2.651 for crystalline material, up to 2.91 for crypto crystalline |
| Sources / Occurrence |
Extremely widespread |
| Varieties |
Crystalline Quartz—Amethyst, Citrine, Ametrine, Vermarine/Prasiolite, Rock Crystal, Smoky Quartz, Rose Quartz
Crypto crystalline Quartz—Agate, Aventurine, Bloodstone, Cornelian, Calchedony, Chrysocolla Quartz, Chryoprase, Fire Agate, Jasper, Pertrified Dinosaur Bone, Petrified wood, Prase, Sard, Sardonyx, Tiger’s eye and Turritella. | | |
| The Quartz group holds a very important place in mineralogy because of the abundance of varieties and its ancient origin. | |
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