Boulder Opal Cabochon

Boulder Opal comes from multiple places in Australia. At one point much of Australia was a sea.  It eventually dried up and formed rock and silica rich water infiltrated the stone and formed opal in the pockets.

The cabochon measures 33 x 25 x 6.5 mm.  It has a girdle height approx. 3.0 mm and is sloped at 5 degrees for ease in setting.  The back is also polished.

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