Tiger's Eye, Wood-Grain in Stone

Tiger's eye is a chatoyant quartz: a former fibrous mineral, the blue asbestos crocidolite, was progressively replaced by silica while its parallel fibre structure was preserved, so light reflecting off the aligned fibres produces a shifting band, the eye, that moves as the stone is turned. The iron in the original fibres oxidised to give the characteristic golden-brown; the blue-grey unaltered stage is sold as hawk's eye, and the red as ox-eye or after heat treatment.

Because the fibres are pseudomorphed rather than loose, cut and polished tiger's eye poses no asbestos hazard. It was cut in quantity from South African deposits from the nineteenth century, which is when most of its popularity dates from; earlier attributions are thin, though a protective, watchful symbolism naturally attaches to a stone that looks like an eye. Its modern metaphysical placement with confidence and the solar plexus is colour-led and recent.