Double-sided Koroit Pendant Opals with faceted Sapphire round beads and Azurite Chryscolla Beaded Necklace.

Boulder Opal is a beautiful, precious opal unique to the Koroit mines in Queensland, Australia. Formed in ironstone with veins of silica and water.

Tiny spheres of hydrated silica arrange three-dimensionally. When white light meets the spherules of silica the light is diffracted in different directions and assumes different colors of the rainbow.