Five Mexican rainbow obsidian cabochons in varied shapes, from 24 to 30 mm. The rainbow effect —bands of green, blue, purple, and gold that emerge with movement— is an optical phenomenon of internal nanolamellae, not a treatment. Selected at a wholesale lapidary market.
Item details
| Mineral |
Rainbow obsidian (volcanic glass with nanostructural iridescence) |
| Dimensions |
RO6: 30×17×8 mm · RO9: 25×20×10 mm · RO13: 24×17×9 mm · RO16: 26×22×10 mm · RO20: 25×20×9 mm |
| Shape and back |
Varied shapes (oval and freeform), flat back |
| Finish |
Mirror polish |
| Hardness |
5–5.5 Mohs — we recommend a closed bezel setting to protect the edges of the volcanic glass |
| Origin |
Mexico |
| Treatment |
Untreated |
| Item type |
Available in 5 formats |
This particular piece
The rainbow effect of these pieces is clearly visible in photographs with raking light, but their true potential is revealed in motion: when the piece is rotated, the color bands shift and change in hue, transitioning from emerald green to deep blue and violet purple within a few degrees of rotation.
The five formats offer a variety of aspect ratios: from the elongated RO6 (30×17 mm) to the almost square RO16 (26×22 mm), passing through intermediate rounded formats. The thickness of 8–10 mm ensures a sufficiently pronounced dome for a quality mirror polish.
How rainbow iridescence is formed
Rainbow obsidian contains parallel-oriented nanolayers of magnetite and hematite, formed during the slow cooling of volcanic glass.
For which setting it works
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Closed bezel setting in 925 silver — the black bezel of oxidized silver enhances the black background of the obsidian and makes the rainbow stand out with more contrast. The perimeter closure protects the edges of the glass.
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Silver pendant necklaces — the rainbow effect is most visible when the piece can move. A pendant with a swivel bail or on a long chain maximizes the optical display.
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Wire wrap with dark silver wire — aged fine silver wire or matte silver wire wraps irregular shapes well and does not distract from the color effect of the stone.
Rainbow obsidian in lapidary tradition
Obsidian has been a trade item in Mesoamerica since the Middle Preclassic (1000 BCE).
In crystal tradition, rainbow obsidian is associated with joy and with integrating one's different facets, qualities that many link to the mineral's multicolored nature.
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 rainbow obsidian
Genuine rainbow obsidian shows the iridescent effect only under certain light angles: if the rainbow is visible from all angles simultaneously, it is probably coated plastic. The conchoidal fracture with sharp edges is visible in unpolished areas. The density (2.35 g/cm³) is greater than plastic.
Frequently Asked Questions
Where does this rainbow obsidian come from?
Mexico is the main source of lapidary-quality rainbow obsidian, especially the states of Jalisco and San Luis Potosí. The material was acquired at a wholesale lapidary market; the piece does not include an independent certificate of origin.
Is the rainbow effect visible in photographs?
Yes, especially with side raking light or flash from an angle. The product photographs use oriented lighting to show the effect. In the finished jewelry, movement enhances the visual impact much more than any static photograph.
Does it have any treatment?
Untreated. The iridescence is an intrinsic optical effect of volcanic glass, without dyeing, coating, or subsequent treatment.
What is the dimensional tolerance?
The dimensional tolerance of the cabochon is ±0.5 mm in any direction.
How is obsidian cared for?
Soft dry or slightly damp cloth. Avoid direct impacts on the face: volcanic glass can chip from point impacts. See also Care for your jewelry.
More varieties of obsidian and volcanic minerals in our cabochon collection.
