PINK OPAL FROM AUSTRALIA

ROUGH SLAB

This is a natural untreated specimen slab 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.. These opals range from opaque to translucent.. This may be kept as a specimen cut into stones or made into a carving.We have taken the photo with the stone wet as this is how it will look polished.

This is what the West Australian mine dept says about Pink Opal
<!—[if gte mso 9]><xml>

</xml><![endif]—>

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 .