Freeform elongated cabochon of Australian opal from Lightning Ridge (New South Wales, Australia). Dimensions: 17.72 × 7.30 × 2.58 mm, weight 1.90 ct. Unidirectional blue-green flash band on N8 body (white with grayish tones).
Item Specifications
| Mineral |
Australian Opal (hydrated mineraloid, SiO₂·nH₂O) |
| Dimensions |
17.72 × 7.30 × 2.58 mm |
| Weight |
1.90 ct |
| Shape and Back |
Elongated freeform, polished flat back |
| Body Color |
N8 (white with grayish tones) |
| Play of Color |
Unidirectional blue-green band running along the long axis of the piece |
| Finish |
Mirror polish |
| Hardness |
5.5–6.5 Mohs — we recommend a closed bezel setting to protect the edges |
| Origin |
Lightning Ridge, New South Wales, Australia |
| Treatment |
Untreated. Opal contains water in its structure; no stabilization or impregnation process has been applied. |
| Item Type |
Unique piece |
This Specific Piece
What defines nr. 16 is its play of color in a band: a stripe of blue-green flash that crosses the long axis of the piece from end to end. The effect is unidirectional — the band appears clearly within a range of angles and disappears outside that range, revealing the underlying grayish body.
The elongated proportion (17.72 × 7.30 mm, ratio ≈2.4:1) was a deliberate lapidary decision: the spherical silicon pattern responsible for the play of color extended in that direction in the original fragment, and reducing it to a squarer format would have sacrificed the band.
How Play of Color Forms in Opal
Opal's play of color is an optical phenomenon caused by diffraction, not pigmentation. The internal structure is made up of hydrated silica spheres — between 0.15 and 0.30 micrometers in diameter — arranged in regular layers that act as a three-dimensional diffraction grating.
Suitable Settings
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Pendant with custom 925 silver setting — the elongated proportion and band effect make this piece a natural pendant
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Closed bezel setting (925 silver or other precious metals) — the 5.5–6.5 Mohs hardness requires full side protection.
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Wire wrap — an alternative for those who work with wire settings; the elongated shape makes it easier to build a wire structure that frames the band without crossing it.
Australian Opal in Lapidary Tradition
Lightning Ridge is the most famous opal-producing region in the world. The first documented finds date back to the late 19th century, when prospectors began working the black clays of northwestern New South Wales. The term opal probably derives from the Sanskrit upala ("precious stone"), via the Latin opalus. Pliny the Elder described opal in the 1st century AD.
In crystal traditions, opal is associated with creativity, multiple vision, and the ability to perceive beauty in the ephemeral — qualities that resonate with the very character of the mineral: a stone that changes color with the angle, never the same from two different positions.
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 Australian Opal
Authentic opal exhibits a play of color that changes with the viewing angle — it is not a fixed iridescence. Under magnification, the surface shows a homogeneous texture without bubbles, glued layers, or visible joints (indicators of doublet or triplet).
Frequently Asked Questions
Does this opal really come from Lightning Ridge?
Yes. This cabochon was acquired directly from specialized Australian suppliers and cut in our workshop. Lightning Ridge (New South Wales) is the primary source of high-intensity play-of-color opal in Australia.
Has it received any treatment?
No detectable treatment. Opal contains between 3% and 10% water in its internal structure; no stabilization or resin impregnation process has been applied. Declaration based on lapidary observation; the piece does not include formal gemological certification.
See also: all cabochons · lapidary collection.
