Glittering Stones >> Semi
precious stones >> Olivine
Semi Precious Stone Olivine
The mineral olivine is an orthosilicate of magnesium
with the formula (Mg,Fe)2SiO4, in which
the ratio of magnesium and iron is found to vary between the 2 end members
of forsterite[?] (Mg-rich) and Fayalite [?] (Fe-rich). Olivine
crystallizes in the orthorhombic system in somewhat flattened
forms but may occur massive or granular. It has a concordat fracture and
is rather brittle. The hardness of olivine is 6.5-7, its specific gravity
is 3.27-3.37 and it has a vitreous luster. It is usually colored olive-green
(hence the name), though it may be reddish from the oxidation of iron.
It is transparent to translucent. Olivine occurs in both igneous rocks
as a primary mineral and in certain metamorphic rocks, and has also been
discovered in meteorites.
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Historical Facts of Olivine
| Refractive index |
1.630–1.650, 1.650–1.670, 1.670–1.690 |
| Chemical Composition |
(Mg, Fe)2SiO4 |
| Mohs Scale Hardness |
6.5 – 7 |
| Density |
3.27 – 3.37 |
| Crystal system |
Orthorhombic |
| Luster |
Vitreous |
| Color |
Yellow to yellow-green |
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Gem Jewelry Olivine
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