Cyrastalline Opal - 7.31 Ct.. Mintabie opal field, Mintabie district. North West Province. South Australia. Au...

Description

Cyrastalline Opal - 7.31 Ct.
Mintabie opal field, Mintabie district
North West Province
South Australia
Australia

This crystalline Opal has a transparent milky white body and rich "fire." Fire in Opals is a phenomenon caused by diffraction. Opals are formed when water percolates through sediments, becoming rich in dissolved silicates. When the water enters a cavity, the silicates are deposited as microscopic spheres, forming Opals. Depending on how the spheres are stacked, and, if they are uniform, they will diffract light. The size of the microscopic spheres dictates the color diffracted back at the viewer. This triangular shaped cabochon features bursts of red-orange, green and violet depending on how the stone is viewed. This "noble opal" is in pristine condition and a true treasure.
Measurements: 17.8 x 15.6 x 4 mm, 7.31 cts.
Offered at no reserve.

[Scale: 1 inch, with mark at 1 cm]

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