Peridot (chrysolite, olivine) is only green: pale yellowish-green, olive-green, dark green, bright-light green (the last is the most valuable colour). The best material arrives from Pakistan, from the areas close to the Afghani border. Big peridots from Kashmir have an intensive colour and they are sold for the high price.
Peridot is idiochromatic gemstone; it means that its colour depends on the basic chemical compound of the stone (iron), instead of the impurities which paint the stones. The material is transparent, but can contain various inclusions. The most usual of them are “lilies” and the “fingerprints” consisting of tiny drops of quartz glass. Also there are dark, brownish-yellow leaves of biotite micas, small pirop and spinel crystals, small black inclusions and “silk” (reflexion of the fibrous inclusions creating a sensation of silk). A shine range is from glassy to greasy. The effect of “the cat’s eye» and asterism are very seldom.
Estimation of peridot
High cost of the large, intensively painted stones reflects not only the difficulty of the extraction of big, “pure” raw stone, but also time for its cutting and polishing. To buy peridot of the pale colour is easier and more cheaply.
Hardness from 6,5 to 7 on Moos scale
Density from 3,27 to 3,37
Factor of refraction from 1,64 to 1,69
Crystal lattice: prism. Peridot is found in a kind of flat prismatic crystals with appreciable grooves on length. Gemological name of the stone is olivine.
Deposits of peridot: Australia, Brazil, China, Egypt (St. John’s island), Myanmar (Burma), Pakistan, Southern Africa, the USA (Hawaii, Arizona), Zaire.