6.90 ct Australian Boulder Opal, Cabochon, No Treatment

Boulder opal forms in thin seams inside ironstone boulders in western Queensland. The cutter keeps a layer of the host rock as a natural backing, which is why the colour looks so vivid against the dark base. This freeform cabochon shows electric blue and green bars of colour across most of its face.

The stone is solid natural opal on its own ironstone, not a doublet or triplet, and it has not been treated. Boulder opal is not hydrophane, and the ironstone makes it tougher than most precious opal, although it still needs a setting that protects the edges.

The outline follows the natural seam, so no two boulder opals look the same. It suits a bezel-set pendant or a ring designed around the shape. The back shows ironstone with thin streaks of opal, which is normal.

Every order ships fully insured from Jaipur by express courier with tracking, usually within two business days of payment. Shipping is free on orders over $250. Import duties and taxes in your country, if any, are paid by the buyer.

If a stone is not what you expected, tell us within 7 days of delivery and send it back in the condition and packaging it arrived in, together with any lab report. We refund the item price as soon as the stone is back with us.

This stone has a lab report: In-house report; third-party lab report available on request

Any stone can be sent to an independent gemological laboratory for a report before it ships. Lab fees and turnaround depend on the laboratory, so ask us for a quote before you order. If a stone already has a report, it is listed under Certificate in the gem details.