This is an Australian solid boulder opal with hole drilled through worn on silver necklace from Queensland.
Incredible mixed of blue, aqua, mint green and purple 100% natural.
Measuring : 15mm x 6mm

More than 90% of the world's precious opals come from Australia.

Boulder opal are found only in the state of Queensland. 

An unique type of opal which is found attached to a host rock, ironstone. The line will always have an uneven appearance.