Opal · Buying Guide
How to Buy a Genuine Opal
Opal is unlike almost every other gemstone in the catalog — it isn't a crystalline mineral at all, but hardened amorphous silica, and its signature play-of-color comes from microscopic silica spheres bending light rather than from any pigment in the stone. Buying it well means understanding both what creates that color and how fragile the material actually is.
Most fine opal reaches the market with minimal treatment beyond cutting and polishing, but the trade does use doublets and triplets — a thin slice of natural opal glued to a dark backing (and, for triplets, capped with a protective quartz or glass dome) to imitate a thicker solid stone at a fraction of the cost. These constructed stones are legitimate products but must be clearly disclosed as doublets or triplets rather than sold as solid natural opal, and synthetic opal and glass "opalite" imitations circulate at the low end of the market as well.
Play-of-color is the dominant value driver — the intensity, pattern, and range of spectral colors flashing across the stone as it moves, with a full spectrum showing red flash (the rarest and most valuable), through orange and green, down to the more common blue. Body tone matters almost as much: black opal, which shows a dark background that makes its colors appear to glow, is the most prized category, followed by crystal (semi-transparent) and white/light opal, where the same play-of-color reads more softly against a pale background. Pattern also plays a role, with harlequin (mosaic-like tiled color patches) and pinfire patterns commanding premiums over more common flash patterns.
Opal is notably softer and more fragile than most gemstones (roughly 5.5-6.5 on the Mohs scale) and, because it contains a meaningful amount of water within its structure, it can crack or "craze" if it dries out too quickly or experiences sudden temperature change — worth knowing before you buy, since care and setting matter more for this stone than for almost any other in the catalog. Ethiopian opal specifically is often "hydrophane," meaning it can temporarily absorb water and change appearance, which is a useful thing to ask about rather than discover after purchase.
For certification specifics, see our Opal certification guide, or check current Opal prices. General authenticity standards that apply across every gemstone we handle are covered on the site-wide Authenticity & Certification page.
Common Opal Buying Questions
What is an opal doublet or triplet, and is it a bad thing to buy?
A doublet or triplet is a thin slice of natural opal bonded to a backing (and, for triplets, capped with a protective dome) — a legitimate, more affordable product as long as it's clearly disclosed, but it should never be priced as if it were solid opal.
Why does my Ethiopian opal look different after wearing it in water?
Much Ethiopian opal is hydrophane and can temporarily absorb water, altering its clarity or color until it dries out again — this is a normal characteristic of the material, not damage, but it's worth knowing about before you buy.
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