Coober Pedy Shell opal stones were formed as an opalized
shell and may have been polished to bring out beautiful colours.
They maybe parts of the shell and most have bright colors
and are popular to make into opal pendants.
Please not most of these opals are not suited for opal ring.
Most opal shell stones are listed with maximum depth indicated but a sit is
shell the other end may not be so thick
Contact seller direct if you want to make into opal ring so
they can advise you its minimum thickness.
Opal shell in Coober Pedy have been mined at Shell Patch and
13 mile, both have reputation of producing good opalized shells