Sillimanite cat’s eye is a gemstone fibrous in nature, producing a chatoyant effect which resembles the winking of a cat’s eye. A changeable luster is displayed as a moving band of narrow white light.

An aluminum silicate in chemical composition, sillimanite is often mined in places containing metamorphic minerals. In the past, deposits were mined in Burma, Kenya, Sri Lanka, and the United States.

Until recently sillimanite cat’s eye was a rare collector’s item. Fresh sillimanite deposits have been found in India and the gemstone became more available to the general public.

Sillimanite exists in various shades, including blue, brown, gray, green, white and colorless. When displaying chatoyancy, the stone may be violet-brown. This translucent gemstone has a vitreous pearly luster.

Sillimanite is also known as fibrolite. With a hardness of 6.5 to 7.5 on the Moh’s scale, it is hard, brittle and can crack. Jewelers fashion it into bracelets, brooches, earrings, necklaces, and rings.

Sillimanite can be cut into facets, beads, or cabochons. Facets are small plane surfaces, while a cabochon cut has a highly polished, rounded, convex form.

The mineral sillimanite is named after its discoverer, American Benjamin Silliman (1779-1864).

Sillimanite is believed to give the wearer increased energy and self-confidence. It aids in the production of endorphins and heals ailments related to the throat and heart.