Black opal, explained
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The rarest opal on earth
Black opal isn't black the way onyx is black. The name refers to the stone's body tone: a dark potch background that makes the play-of-color sit up the way stars do in a country sky. Almost all of it comes from one place: Lightning Ridge, New South Wales — the ground itself is worth reading about in the Lightning Ridge guide.
Body tone is graded from N1 (blackest) to N9 (white). N1–N4 is called black opal; N5–N6 dark opal. The darker the body and the stronger the color, the rarer the stone; a bright red-on-black flash is the rarest combination opal produces.
Pattern, and the words worth knowing
After body tone and brightness, pattern is what separates a good black opal from a great one. Harlequin is the one everyone wants and almost nobody sees: distinct angular patches of color tiling the face like stained glass. True harlequin opal is rare enough that most stones sold under the name are really broad flash, which is the next tier down and still excellent — large sweeps of a single color rolling across the stone as it moves.
Below those: rolling flash, floral, ribbon, straw, and pinfire, which is thousands of tiny points of color. Pinfire is common and pretty and priced accordingly. And then there is the color itself. Red is the rarest; red-on-black is the top of the market. A stone described as "black opal fire" is usually just being sold with an adjective — ask for the body tone number instead.
Black potch, by the way, is the same material with no play of color at all. It is what most of a Lightning Ridge parcel actually is, it is what a doublet backing is often made from, and it is worth knowing the word so you recognise it when a seller uses it about a stone's back.
What black opal costs
Fine black opal runs from a few hundred dollars per carat for smaller stones with modest color to five figures per carat for gem-grade broad flash on an N1 body. Because the variables interact, a single number is useless — the per-carat bands by body tone, brightness and pattern are set out in the black opal price guide.
The short version: if a 'black opal' is cheap, it is almost always a doublet, a triplet, a treated Ethiopian stone, or lab-created. All legitimate products when disclosed, and all a different thing.
Ask three questions of any seller: Is it solid? What's the body tone (N-scale)? Where was it mined? A seller who can't answer all three quickly isn't selling black opal.
From Opalani
We carry Lightning Ridge black opals, each one-of-one, cut by hand, and certified, with body tone and origin stated plainly.
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