11.75 ct Boulder Opal

11.75 ct Natural Queensland Boulder Opal

This vibrant 11.75 carat natural boulder opal displays classic Queensland characteristics: brilliant flashes of colour in thin veins of precious opal embedded within dark ironstone host rock.

Queensland boulder opal forms exclusively in Queensland's outback, where silica-rich water deposits microscopic spheres in cracks and voids of ancient ironstone boulders. The result is a durable gem with striking contrast between fiery play-of-color and earthy matrix—often resembling miniature landscapes.

Tied to the ~100-million-year-old Winton Formation, these opals are geologically ancient and rare. High-quality pieces with intense color and appealing patterns are limited by sparse, remote deposits, making Queensland boulder opal one of Australia's most prized varieties after black opal.

A unique Australian treasure capturing timeless rarity and wild beauty.