Glittering Stones >> semi
precious stones >> Garnet
Semi Precious Stone Garnet
The garnet group of minerals usually shows crystals
with a habit of rhombic dodecahedrons and also with trapezohedrons. They
are nesosilicates with the same general formula, A3B2 (SiO4)3. The chemical
elements in the garnet include calcium, magnesium, aluminum, iron2+, iron3+,
chromium, manganese, and also titanium. Garnets show no cleavage and a
dodecahedral parting. Fracture is a concordat to uneven; some varieties
are very tough and are also very valuable for abrasive purposes. Hardness
is 6.5 - 8.5, specific gravity is 3.1 - 4.3, luster is vitreous to resinous,
and that they can be transparent to opaque.
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Historical Facts of Garnet
| Refractive Index |
1.72 - 1.94 |
| Crystal System |
Cubic |
| Chemical Composition |
X3Y2(SiO4)3 |
| Mohs Scale Hardness |
6.0 - 7.5 |
| Major Varieties |
Pyrope, Almandine, Spessartite, Andradite, Grossular, Uvarovite |
| Colors |
Red, orange, yellow, green, blue, purple, brown, black, pink and colorless |
| Occurrence |
Macon County, North Carolina, United States, Russia, Turkey |
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Gem Jewelry Garnet
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