Peridot, olivine

August peridot (olivine) (Mg.Fe SiO, yellow-green Fe2 Crystal field transitions in Fe" in two distorted six-coordinated sites. 

Peridot is the gem variety of olivine, a magnesium silicate containing iron (about 9 Mg atoms for every Fe atom). Peridot is usually transparent,... 

The materials most commonly used as gems and ornamental stones are listed in Table 2.9. This is by no means a complete listing of all materials ever used in jewelry or for decorative purposes. There are many worked specimens that are one-of-a-kind, made from unexpected materials that were opportunistically obtained. These often pose problems of identification and consequently of conservation, since once a stone has been worked it loses its natural luster and form. Stones have been altered with dyes and heat for thousands of years, so it does not hold true that just because something is in an old artifact or Grandma s necklace that it cannot be dyed or otherwise not natural. Synthetics are relatively new, but imitations are as old as the stones themselves. If someone wanted a red gem, and there were no rubies available, then a garnet or spinel could be used instead. No emeralds Use an olivine (peridot) or green sapphire. A synthetic must have the same composition and internal structure as the natural material, but an imitation just has to look like the natural stone. 

Gaetani G. A. and Grove T. L. (1999) Wetting of mantle olivine by sulfide melt implications for Re/Os ratios in mantle peridot te and late-stage core formation. Earth Planet. Sci. Lett. 169, 147-163. 

The best-known composition of olivine, the light green gemstone peridote, is (Mgo.9Feo.i)2Si04. The olivines are a group of minerals showing isomorphous replacement. 

Peridot is better known as the mineral olivine. The gemstones usually have a composition close to (Mgo9,Feo i)2Si04 and have a unique green color. It was mined for 3500 years on the island of Zabargad (St. John s... 

Olivine is one of the most common minerals on Earth, also found in meteorites, on the Moon, Mars, etc. and it is of olive green color. Transparent olivine is sometimes used as a gemstone called peridot. 

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