The family that includes Bulls Eye (sometimes called Red Tiger Eye) are banded quartz, which have a beautiful chatoyancy that arises from fibrous inclusions of amphibole fibres or crocidolite (asbestos), which makes them appear to be banded. Bulls Eye, which is deep red/brown, contains iron in the asbestos mix. The basic colour of most banded quartz is blue/black, (Hawks Eye) which contains fibres of blue/black crocidolite. When this mass oxidises the crocidolite turns to limonite and forms the yellow brown fibres known as Tiger Eye. Other common forms of banded quartz arise from the same base material: this mineral, Bulls Eye, and Cats Eye, which is a paler grey/green with a lower concentration of crocidolite.
Bulls Eye is an effective energising and grounding stone. It can be of use to help open and stabilise the base chakra especially, but can warm and energise any chakra or centre. A nice gentle, yet useful, stone for the beginner.