"Owyhee" blue opal cabochons from Oregon (USA), in five sizes from 23 to 38 mm. Common opal with intense sky blue to pearly gray color, without play-of-color (different from precious opal). Selected at a wholesale lapidary market.
Piece Details
| Mineral |
Owyhee Blue Opal (common opal, SiO₂·nH₂O) |
| Dimensions |
no.12: 24×20×5 mm · no.16: 38×22×6 mm · no.33: 23×16×7 mm · no.35: 36×15×6 mm · no.39: 25×34×6 mm |
| Shape and Back |
Varied shapes (oval, teardrop, freeform), flat back |
| Finish |
Mirror polish |
| Hardness |
5.5–6 Mohs — we recommend bezel setting; opal is sensitive to impacts and dehydration |
| Origin |
Owyhee Region, Oregon / Idaho, United States |
| Treatment |
Untreated |
| Piece Type |
Available in 5 sizes |
This specific piece
Owyhee blue opal is an opaque common opal, without the play-of-color of precious opal. Its appeal lies in its uniform blue color, which ranges from bright sky blue to pearly grayish blue depending on the size and intensity of the mineralization. Some sizes show a slight "milky" effect in transmitted light, adding depth to the color perception.
The largest size (no.16, 38×22 mm) has the most presence; no.33 (23×16 mm) and no.12 (24×20 mm) are the most comfortable for rings and everyday pendants. Size no.39 (25×34 mm, taller than wide) is peculiar in proportion and very striking in asymmetric earrings.
How Owyhee blue opal is formed
Owyhee opal is a hydrothermal hydrophane opal formed in cavities and fissures of basalt in the Owyhee River region, on the border of Oregon and Idaho (USA).
What setting it works for
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Closed bezel setting (925 silver or sterling silver) — the bezel protects the edges of the opal and also helps maintain the relative humidity of the stone during use.
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Medium silver pendants — the 23–38 mm range of available sizes covers everything from discreet pendants to statement earrings.
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Wire wrap with fine silver wire — opal tolerates wire wrap if the wire does not exert pinpoint pressure.
Opal in lapidary tradition
The term "opal" derives from the Sanskrit upala (precious stone) and was adopted by the Latin opalus.
In crystal tradition, opal is associated with inspiration and emotional amplification. The specific blue of Owyhee is linked with serene communication and intuition.
The symbolic properties attributed to minerals belong to cultural and historical traditions. They are shared for educational purposes, not as medical advice or a substitute for professional care.
How to recognize genuine blue opal
Genuine blue opal has a blue that varies slightly in tone between pieces and shows some translucency in the central area when lit from behind. Glass or blue plastic imitations have an excessively uniform color without the translucent depth of opal. Genuine opal has a density of 2.0–2.2 g/cm³ (lighter than most stones); the polished surface is noticeably warmer to the touch than cold glass.
Frequently asked questions
What is the difference between Owyhee blue opal and precious opal?
Precious opal (Australian, Ethiopian, Mexican) has play-of-color: iridescent flashes that change with the angle. Owyhee blue opal is a common opal without play-of-color; its appeal lies in its uniform blue color and its North American origin, which gives it its own lapidary identity.
Can opal get stressed or crack?
Owyhee opal has a relatively high water content. In very dry environments, it can lose moisture and develop microfractures (crazing). We recommend storing it in an environment with normal relative humidity and not leaving it in direct contact with the sun or heat sources.
Does this piece have any treatment?
No detectable treatment. No apparent coating or impregnation. Statement based on lapidary observation; the piece does not include gemological certification.
More opals and pieces from the United States in our cabochon collection. See also: properties of opal.
