Australian Opal Nugget set in Sterling Silver Necklace with Chain

Vintage artisan made sterling silver pendant and chain necklace. The pendant is set with a large Australian stone. The opal is natural with only a polished front surface and natural host rick backing. The opal has inner crazing which sometime happens when it is brought out of the mine into the air. It has purple and gold play of color.  The stone measures 30mm by 20mm and 11mm thick. Marked 925 on the bail. Pendant with bail is 1 5/8" long. Sterling Silver box chain is 18" long. Weight: 10.2 grams.