Tiger's Eye: Mineral information
Tiger Eye is a gorgeous, chatoyant, semi-precious gemstone with alternating banks of golden to red-brown colors and a silky luster. It has a fascinating and constantly shifting light effect in which the gold and brown bands appear to keep reversing as the stone is moved relative to the light source. This effect is caused by the light reflecting off of microscopic fibers of crocidolite (a blue form of asbestos) within the stone.
An
optical phenomenon, possessed by certain minerals in reflected light,
in which a movable wavy or silky sheen is concentrated in a narrow band
of light that changes its position as a mineral is turned.
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Tiger's Eye Stones. Photo: Adam Ognisty |
As members of the quartz group, tiger's eye and the related blue-coloured mineral hawk's eye gain their silky, lustrous appearance from the parallel intergrowth of quartz crystals and altered amphibole fibres that have mostly turned into limonite.
Tiger's Eye forms when Quartz forms over existing bluish-gray Crocidolite, and eventually entirely replace it. Crocidolite is a type of asbestos mineral, which means its composition is of fine, dense fibers. These fibers form in a parallel yet wavy orientation, and this causes the intriguing chatoyant effect exhibited in Tiger's Eye. During the replacement process, the iron within the Crocidolite dissolves and stains the Quartz, thereby providing the golden yellow to brown color of the Tiger's Eye.
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Set of various tiger-eye natural mineral stones and gemstones (tigers eye, bull-eye, hawk-eye). Copyright : Vvoennyy |