Rainbow Calsilica is a recently discovered multi-colored layered stone
being used for Zuni fetish carvings as well as beads and cabochon cut
Rainbow Calsilica is a microcrystalline calcite bonded with the
amorphous clay mineral allophane. Silica is also present. It has been
described as vein matter or fracture fill formed when a copper push
cut into volcanic rhyolite host rock. A stabilization process similar
to that used with turquoise has been applied to it.