The 72-Carat Virgin Rainbow Opal

Found in Coober Pedy of southern Australia by John Dunstan, the famous 72-carat Virgin Rainbow opal is one of the most valued opals in the world. The Virgin Rainbow is an opalized fossil, meaning the initial formation of this opal replaced a fossil; most likely from an ancestor of a cuttlefish. The evolution of this opal most likely began with a dead cuttlefish on the seafloor. As sediment covered the fish, surrounding sediments lithifide into rock as the shallow sea dried, evolving into a desert. Meanwhile, silica rich fluids within the rock deposited inside the cavity where the cuttlefish once remained; forming this hydrous complex silicate (opal). Currently, the Virgin Rainbow is valued for over $1million USD. ............................................................................. #science #mineralization #nature #education