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Australia is the world leader in opal production. Some of the most attractive Australian opals are those typically formed in ironstone boulders in the state of Queensland. The article by Richard Wise in this issue provides an overview of Queensland boulder opal, with specific information from an active operation, the Cragg mine. The opals illustrated here—shown on a classic opal-bearing Queensland boulder—all have some of the ironstone matrix as a backing. The large gem opal is 47.05 × 37.65 × 8.36 mm thick; the smallest piece is 13.44 × 8.55 × 2.00 mm thick. All are from the collection of George Brooks, Santa Barbara, CA. Photo © Harold & Erica Van Pelt—Photographers, Los Angeles, CA. |
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