Tumbled tiger's eye A member of the quartz group, it is a classic example of pseudomorphous replacement by silica of fibrous crocidolite (blue asbestos). The chatoyance is caused as light is reflected by fibres in the stone. Tiger’s eye acts as a mirror: it repels negative energies towards the transmitter. A protective stone, it can be worn or placed near the entrance of a house. A stone of mobility, it is associated with the knee chakras: physically it strengthens bones and joints; psychologically it promotes energy and self-confidence.