PINK OPAL FROM AUSTRALIA

ROUGH SPECIMEN

This is a natural untreated specimen found in the Gascoyne region near Carnarvon in West Australia in 2011- previous to this only pink opal was from Peru. This material has various shades of pink with interesting white lines through some specimens.The pink opal derives its color from trace amounts of included organic compounds known as quinones. These opals range from opaque to translucent.. This may be kept as a specimen cut into stones or made into a carving.

This is what the West Australian mine dept says about Pink Opal

Pink opal ‘Pink opal’ is a prospectors’ name applied to a different variety of mookaite that outcrops as a persistent bed of extremely bright pink opalized radiolarite near Binthalya. At this site, pink opal is present as a dominant, horizontal bed within zones of coloured porcellanites located beneath a surface-brecciated zone in which angular fragments of pink porcellanite have been cemented by iron and silica solutions to produce an attractive pink breccia. The pink zone beneath has already been tested by trial mining to ascertain the extent and consistency of the pink, opalized material.

Examination of pink opal thin sections has confirmed the rock is radiolarite with a dominantly isotropic, finegrained mineral composition. Although not verified by XRD analysis, the pink opal’s physical and visible optical properties suggest it is predominantly opaline silica, having a lower bulk density than the locally porcellanized mookaite material. Pink opal commonly shows liesegang banding and often contains small vugs and fine fractures infilled with microcrystalline quartz. Microscopic, lustrous grains within the rock result from reflections of granular quartz where it has infilled pores and replaced radiolarian structures. In a manner similar to the origin of mookaite, the resilicification of the Windalia Radiolarite forming the pink opal porcellanite has resulted in a visually attractive, bright pink material displaying a high vitreous lustre. Pink opal is extremely hard and brittle with a conchoidal fracture . These properties allow pink opal to take a high polish, making it suitable for the production of colourful, polished tumbled stones, cabochons, and other artworks .