Opal price: what a precious opal is worth per carat
Opal is priced unlike faceted gems: value comes from its play-of-colour — the flashing rainbow within — plus body tone, brightness and pattern.
What drives opal price
Precious opal is valued for play-of-colour: the shifting spectral flashes seen as the stone moves. The strongest, broadest and brightest play across a dark background is the most valuable. Opal is typically sold as cut cabochons and priced per carat, but the factors differ from transparent gems.
Body tone & type
- Black opal (dark body tone, Lightning Ridge, Australia) — the rarest and most valuable, as colour flashes stand out vividly.
- Boulder opal — opal on ironstone host; strong colour, often more affordable than black.
- White/light opal — pale body tone; the most common and generally least expensive.
- Crystal opal — transparent to translucent with play-of-colour.
Brightness, pattern & colour range
Brightness is critical — a dull stone is worth far less than a vivid one. Broad patterns (such as "harlequin") and a full spectrum including red command premiums, since red play-of-colour is the rarest.
Care note
Solid natural opal is valued above doublets and triplets (assembled stones). Origin, mainly Australia and Ethiopia, also affects price.
Opal price — frequently asked questions
Why is black opal the most valuable?
Its dark body tone makes the play-of-colour flash more vividly. Fine black opal, mostly from Lightning Ridge in Australia, is the rarest and most expensive type.
What makes one opal worth more than another?
Brightness and the breadth of play-of-colour matter most, followed by body tone (darker is rarer), pattern, and whether red is present. Red play-of-colour is the rarest.
Are solid opals better than doublets or triplets?
Yes. Solid natural opals are worth more than assembled doublets or triplets, which use a thin opal layer bonded to backing and cap material.
How is opal priced?
Per carat, but on play-of-colour, body tone, brightness and pattern rather than the clarity and cut factors used for faceted gems. Use the calculator for a range.
Indicative trade information from the Gem Index universal pricing engine — not a formal appraisal or laboratory certificate. Wholesale, USD. Species, treatment and origin should be confirmed by an accredited gem laboratory before sale. See our full disclaimer and methodology.