Tuesday, 15 January 2019

'Finest Opal Ever' found

Billed as the “finest opal ever,” the Virgin Rainbow made its world debut at the South Australian Museum in Adelaide as the centerpiece of a larger exhibition to commemorate the centenary of opal mining in Australia.
Veteran miner John Dunstan is credited with discovering the Virgin Rainbow in Coober Pedy in 2003.

Dustan has mined opals for 50 years, but the internal fire of the Virgin Rainbow is unlike anything he’s ever seen.

Gibber plain near Coober Pedy
The Virgin Rainbow is a Belemnite pipe, which is essentially an opal that formed in the skeleton of an extinct ancestor of the common cuttlefish.

It is considered a once-in-a-lifetime discovery.
Coober Pedy is called “The Opal Capital of the World.” The discovery of gem opals sparked a rush of mining activity that has generated top-quality gems for more than 100 years.

Australia produces more than 90% of the world’s precious opals.
Between 100 million and 97 million years ago, Australia’s vast inland sea began retreating. As the sea regressed, a rare episode of acidic weather was taking place, exposing pyrite minerals and releasing sulphuric acid.

As the surface of the basin dried further and cracked, silica-rich gel became trapped in the veins of the rock. Over eons, the silica solidified to form opals