Learn
A small, honest knowledge base — origins, patterns, terms, care. Drawn from twenty-plus years at the bench. Read in any order; come back when a stone surprises you.
We cannot see our reflection in running water.
It is only in still water that we can see.
Where opals come from
New South Wales, Australia
The dark body that makes color shout — N1–N4 on the body-tone scale
The most prized opal field in the world. Mined from sandstone seams, the dark potch behind the color is what gives Lightning Ridge its electric quality. A vivid green-blue flash on a true black body is what every cutter dreams about.
South Australia
Bright play-of-color on a light body — clean, classical opal
The world's biggest source of white opal. Lighter body, but the play-of-color can be just as vivid as Lightning Ridge — sometimes more. Coober Pedy stones are how most people picture an opal: milky background, rainbow inside.
Queensland, Australia
Opal pockets inside ironstone — sculptural, one-of-one
Boulder opal sits as veins and pockets inside dark ironstone matrix. Yowah Nuts are little geode-like spheres with color in the middle. Every piece is asymmetric and impossible to repeat — cutting around the color is its own art.
Wollo Province, Ethiopia
Honeycomb pattern, neon flash, drinks water (hydrophane)
Discovered in 2008 and reshaped the opal world. Highly transparent crystal bodies with vivid neon flash — often green, blue, red — sometimes in the rare honeycomb cellular pattern. Welo is hydrophane: it absorbs water and changes appearance. Always dry thoroughly before storing.
Querétaro & Jalisco, Mexico
Body color IS the fire — no play-of-color required
Different beast: a fire opal's value is its translucent body color, deep orange to ruby red. Some Mexican stones also carry a play-of-color, but the prized look is a clean, glowing ember held up to light. Faceted Mexican fire is a stone of its own kind.
Australia / Indonesia / USA
When silica replaced the original organic structure
Sometimes opal grows where something used to be — a bone, a clam, a tree trunk. The original organic material is gone and the silica took its place, sometimes carrying play-of-color, sometimes not. A common-opal fossil with sand and cracks is still a 60-million-year-old wood replaced by mineral. That's worth holding.
How color arranges itself
Many tiny pinpoint flashes, like static color. Usually the first pattern beginners notice.
Large patches of single color sweep across the face when tilted. Bright, easy to read.
Color moves as a wave across the stone with the smallest tilt. The trick is the angle.
Irregular organic shapes — botanical, almost lichen-like. No two are alike.
Color arranges into image-like inclusions: faces, landscapes, animals. Buyer-dependent.
A hexagonal cellular grid of color, almost only found in Welo crystal opal. A cutter may never see one in a lifetime.
Vertical column-like structures of color rising through the stone.
Sharp angular blocks of color of roughly equal size, like stained glass. The most-prized pattern in the world.
Read the listings without guessing
So they last another lifetime
Vibration cleaners can crack opal, especially Welo. Use a soft damp cloth — that's it.
Ethiopian Welo is hydrophane: it drinks water and goes translucent for hours. Pat dry, let air-dry on a soft cloth for 24h before storing.
Direct sun, car dashboards, hair-dryer range — sudden dry heat can craze opal. Store away from radiators.
Opal sits around 5.5–6.5 on Mohs. If you wear it on your hand, choose a bezel setting and take it off before manual work.
Doublets and triplets are glued — don't soak. A damp cloth wipe is the safe move.
Harder stones (diamond, sapphire) will scratch opal. Keep it in its own pouch or felt-lined box.
Where the rough actually comes from
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