Australian boulder opal is a precious opal which forms within cavities and cracks of ironstone boulders.
Australian boulder opal is only found in Outback Queensland.
When cutting this type of opal, the natural host rock is left on the back of the opal which gives the opal its extra strength and colour compared to other opals.
Rough Australian boulder opal specimen.
Dimensions: 40 mm X 33 mm.
Weight: 24 grams.
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