Free-form Australian opal cabochon from Lightning Ridge (New South Wales, Australia). Dimensions: 8.70 × 5.30 × 1.94 mm, weight 0.50 ct. Multi-color play of color — electric greens and blues with yellow flashes — on N8 body (white-grey). Hand-cut in our lapidary workshop.
Item Details
| Mineral |
Australian Opal (hydrated mineraloid, SiO₂·nH₂O) |
| Dimensions |
8.70 × 5.30 × 1.94 mm |
| Weight |
0.50 ct |
| Shape and Back |
Free-form, flat polished back |
| Body Color |
N8 (white with grey hues) |
| Play of Color |
Multi-color — dominant greens and blues, yellow flashes |
| Finish |
Mirror polish |
| Hardness |
5.5–6.5 Mohs — we recommend 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 processes have been applied. |
| Item Type |
Unique piece |
This specific piece
What distinguishes this cabochon is the character of its play of color: despite its small dimensions — less than 9 mm long — the chromatic spectrum occupies almost the entire upper face. Electric greens and blues dominate, but at certain angles, a yellow flash appears, shifting the tone towards a warmer range. The effect is not static: each turn of the piece activates a different color.
The free-form silhouette — irregular, without a defined axis of symmetry — is not accidental. The lapidary chose this outline to take advantage of the area with the highest concentration of spherical silica, where the play of color is most intense. The flat back facilitates setting without creating tension on the material.
How play of color forms in opal
Opal's play of color is an optical phenomenon of diffraction, not pigmentation. The internal structure of quality opal is formed by hydrated silica spheres — between 0.15 and 0.30 micrometers in diameter — arranged in regular layers that act as a three-dimensional diffraction grating. When white light passes through these layers, each wavelength is diffracted at a different angle: the visible result is the palette of colors that changes with movement. The size of the spheres determines which colors dominate — larger ones diffract towards red and orange; smaller ones, towards blue and violet. Opals with a blue-green dominance, like this cabochon, contain spheres of intermediate size with great uniformity of arrangement.
What mounting it works for
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Bezel setting (925 silver or other precious metals) — Mohs hardness of 5.5–6.5 needs side protection; the closed bezel encloses the edge and eliminates the risk of chipping in daily wear. Ideal for a minimalist pendant or solitaire earring.
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Pendant with custom silver mounting — the small size (8.70 mm long) works well as a delicate pendant or an earring. The mounting is custom-made to the stone's free silhouette.
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Wire wrap — alternative for those who work with wire wrapping; use ≥20 gauge wire in silver or gold to avoid scratching the surface during the process.
Australian opal in lapidary tradition
Lightning Ridge is the most famous opal-producing region in the world. The first documented findings date back to the late 19th century, when prospectors began working the black clays of northwestern New South Wales. The scientific term for opal as a mineralogical species was consolidated in 1906, although the mineral had been appreciated for centuries: Pliny the Elder, in the 1st century AD, described it as the stone that concentrates "the fire of the carbuncle, the purple of the amethyst, and the sea-green of the emerald." Romans called opal opalus — a term possibly derived from the Sanskrit upala, "precious stone."
In crystal tradition, opal is associated with creativity, inspiration, and the ability to see from multiple perspectives — qualities connected with the optical phenomenon itself: a stone that displays different colors depending on the angle from which it is viewed.
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 fluidly with the viewing angle — it is not a fixed iridescence like that of labradorite. Under magnification, the surface shows a homogeneous texture without bubbles, glued layers, or visible joints (signs of a doublet or triplet). The specific gravity of natural opal (≈2.1 g/cm³) is lower than that of glass (≈2.5 g/cm³): a genuine piece weighs less than it appears for the same size. Synthetic opals often show a scaly color pattern — a "lizard skin" effect — which looks unnatural under 10× magnification.
Frequently Asked Questions
Does this opal really come from Lightning Ridge?
Yes. This cabochon was purchased directly from specialized Australian suppliers and cut in our lapidary workshop. Lightning Ridge (New South Wales) is the main source of high-intensity multi-color play of color opal in Australia.
Is it suitable for a ring setting or only for a pendant?
The small dimensions (8.70 × 5.30 mm) make this cabochon a more natural choice for a pendant or earring. If set in a ring, we recommend a design with a high bezel that protects the opal from frequent side impacts during hand use.
Has it received any treatment?
No detectable treatment. Opal contains between 3% and 10% water in its internal structure; no stabilization or resin impregnation processes have been applied. Statement based on lapidary observation; the piece does not include formal gemological certification.
Why does the play of color vary so much with the angle?
This is the natural behavior of genuine opal. The play of color is a diffraction phenomenon: internal silica spheres diffract different wavelengths depending on the angle of incidence. As the stone is turned, the angle changes, and so does the color. A piece that does not change color with movement is probably not high-quality natural opal.
What are the exact dimensions, and is there any tolerance?
8.70 × 5.30 × 1.94 mm, weight 0.50 ct. As a unique hand-cut piece, there may be a variation of ±0.5 mm in any dimension. The free-form silhouette means there is no reference axis of symmetry.
How should opal be cared for?
Opal contains water in its structure and can dehydrate in very dry environments, causing surface cracks. Clean only with a soft, damp cloth; avoid ultrasonics, steam, and chemicals. In very dry environments, store with a small piece of slightly damp cotton. More details in care for your jewelry.
See also: all cabochons · lapidary collection.
