Australian White Opal, a solid Opal over 2mm thick, not a sliver of Opal material backed with black potch, or worse, plastic, called “doublets”, or “triplets” when the doublet is capped with a slice of clear Quartz or plastic, to enhance the brightness of the material.
The above 8x6mm oval Australian White Opal solid is from Lightning Ridge, back in the late 1980s. It is a quite good example of the gemstone, nicely displaying the Opal iridescent characteristic “Play of Colour” where flashes of colour appear as the gemstone turns in the light. The strongest flash of colour in the above solid is green.
Another defining aspect of a good Opal is the dispersal of the “Play of Colour” across the entire surface of the gemstone, so that there are no “dead” areas devoid of colour as the Opal is turned in light, and again the above gemstone nicely conforms to that desired quality.

The ring setting of Sterling Silver, created and crafted in Sydney, is very sturdy and quite classic,  cleanly designed and well-proportioned.
The Opal gemstone has been set in Sydney by a master gemstone setter.