A close-up of “Tiger’s Eye”, a gem/semi-precious stone from South Africa.
Tiger’s Eye has a silky lustrous look derived from its many parallel and wavy threads of minerals visible in this macro shot.
The fibres are originally composed of crocidolite, a form of asbestos**. During later stages of formation or subsequent heating they convert to quartz of the same shape. Iron minerals stain the stone with reds and yellows. The darker and bluish areas have incomplete replacement of crocidolite by quartz (Hawk’s Eye). Strong iron staining also gives dark bands.
**Harmless in Tiger's eye unless ground into dust
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