A polished slab with a band of light that moves across the face as you tilt it.
That movement is the whole point of the material. Tiger's eye is built from fibres running parallel through the quartz, and each one reflects light along its length rather than off a flat surface. Turn the slab and the reflection travels, because a different row of fibres is catching the light each time.
It only works with a single light source. Under diffuse daylight or several lamps the effect flattens out, so give it one directional light rather than an evenly lit shelf.
Mineral: Tiger's eye (a variety name, not an IMA species), quartz (SiO₂) with fibrous riebeckite (crocidolite)
Crystal system: Trigonal
Origin: Northern Cape, South Africa
Hardness: 6.5 to 7 on the Mohs scale; durable, though the polished face dulls if knocked about
Treatment: None to the stone. Resin stabiliser applied around the edges
Dimensions: 8.3 x 1 x 25 cm
Weight: 500 g Note: Do not cut, grind or sand it. The fibres running through tiger's eye are crocidolite, locked into the quartz and inert in a finished slab, but power tools release them as dust.
You will receive the exact piece photographed.