Dims: 4.7x2.6x0.4" (11.7x6.6x1.0cm)
Wt: 3.99oz (113.1g)
Hamersley Range, Western Australia
This is a specimen of "Pietersite", a variety of tiger's eye, which is a pseudomorph of quartz after crocidolite. Crocidolite is the asbestisform variety of riebeckite. In Pietersite, the transformation is incomplete, and the lovely blue color is due to the crocidilite (riebeckite) that remains. Properly speaking, the orange chatoyant areas are true tiger's eye, where the riebeckite has weathered to an iron oxide, and quartz has replaced the fibers of crocidolite.