Crystal
Golden bands that slide as the stone turns — asbestos fibres replaced, one for one, by quartz.
These are associations the community holds, not settled fact — the more a reading is shared, the bolder it sits.
The chatoyancy — the moving band of light — comes from parallel fibres. Tiger's eye began as crocidolite, a blue asbestiform amphibole, which was gradually replaced by silica while the fibrous structure was preserved; iron oxidation turned the blue to gold along the way. Where the original blue survives, the stone is sold as hawk's eye. Because the fibres are now quartz rather than asbestos, worked and polished tiger's eye is not an asbestos hazard, though the raw rock in a quarry is a different question.
The great source is Griqualand West in South Africa's Northern Cape, and it has been mined commercially since the mid-nineteenth century. Before that Europe knew the stone barely at all, which puts it in the same category as labradorite and sodalite: a stone whose entire body of lore has been written recently, however ancient the language used to describe it sounds.
Practice gives it courage and steadiness of nerve — an unshowy confidence rather than a fiery one — and quite often protection, on the strength of the eye. That the eye is a nineteenth-century acquaintance and the protective-eye motif is several thousand years older is a decent illustration of how quickly a new stone gets fitted into an old shape.
Readings practitioners have offered, ordered by how many recognise them. Take what serves, leave the rest.
Carried forward
Common in contemporary practice
Carried in a pocket where a thumb can reach it, and turned. The band of light moves with the turning, and practitioners describe the fidgeting as most of the method — a stone that gives the hands something to do while the nerve is gathered.
Carried forward
Common in contemporary practice
Sometimes called a stone against the evil eye, matching eye to eye. The protective-eye motif is far older than any European knowledge of this stone, so what has happened here is an old idea finding a new object rather than the other way round.
Credit what you carry. Much of this comes from living traditions, and some of it from traditions that are closed — held by particular peoples and not offered for general use. Where you know whose practice a reading came from, name them; where you don't, say that too.