Glittering Stones >> Semi
Precious Stones >> Spinel
Semi Precious Stone Spinel
Spinel is one of the groups of minerals that crystallize in
the isometric system with an octahedral habit, and whose chemical compositions
are also analogous. These minerals are combinations of bivalent and trivalent
oxides of magnesium, zinc,
iron, manganese, aluminum and also chromium, the general formula being
represented as R''O•R'''2O3. The bivalent oxides may be MgO, ZnO,
FeO and MnO, and the trivalent oxides may be Al2O3, Fe2O3, Mn2O3 and Cr2O3.
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Historical Facts of Spinel
| Refractive Index |
1.712 - 1.762 |
| Chemical Composition |
MgAl2O4 |
| Hardness |
8 |
| Crystal habit |
Cubic, Octahedral |
| Crystal system |
Isometric |
| Density |
3.54 - 3.63 |
| Luster |
Vitreous |
| Occurrence |
Sri Lanka, Burma, Thailand, Australia, Kenya, Brazil |
| Types of spinel |
Gahnite, Franklinite, Chromite, Magnetite, Hercynite, Ulvöspinel, Jacobsite, Trevorite, Ringwoodite |
| Color |
Orange, Pink, Black, Blue, Lavender, Mauve, Greenish blue, Vivid red |
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Gem Jewelry Spinel
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