What is Tiger-eye?

Tiger-eye is a chatoyant (cats' eye effect) variety of microcystalline quartz, that has replaced the asbestos mineral crocidolite. The fibrous nature of the replaced crocidolite is what gives tiger-eye its phenomenal quality. Fortunately, it is quite abundant, therefore reasonably priced. It has been claimed that tiger-eye has the ability to improve one's eyesight and insight; meditating on tiger-eye in sunlight can enable one to look clearly into the past and the future.