Sunday, January 5, 2020

Garnet

Garnets are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. All species of garnets possess similar physical properties and crystal forms, but differ in chemical composition. The different species are pyrope, almandine, spessartine, grossular, uvarovite and andradite.


Garnets are a group of minerals; which refer to a fairly complex group with a great amount of isomorphic replacement resulting in intermixtures of chemical compositions giving a distinct range of colours.
Of these varieties andradite and uvarovite have not been found in Sri Lanka. As in other gem minerals garnets too occurs in varying degrees of transparency, the fully transparent ones with good colour being the most beautiful. They could also display asterism in the form of a four rayed star. Even chatoyancy has been noted from among the Sri Lankan material as has been established by somebrownish red cat’s eyes. Different varieties of garnets have different properties and these will be discussed separately.

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