Pair of triangular black obsidian cabochons with chamfered edges, 13×13×3 mm, hand-carved in our lapidary workshop. Flat, cleanly cut, designed for bezel-set earrings.
Piece Details
| Mineral |
Black Obsidian (natural volcanic glass) |
| Dimensions |
13×13×3 mm (±0.5 mm due to hand carving) |
| Shape and Back |
Triangular with chamfer, flat back |
| Finish |
Mirror polish |
| Hardness |
5–5.5 Mohs — we recommend closed bezel setting to protect the vertices |
| Origin |
Mexico (Jalisco / Sierra Chichinautzin) |
| Treatment |
No treatment |
| Piece Type |
Pair of 2 pieces |
About this specific piece
The triangular shape with chamfered edges—vertices softened with a 45° cut—is technically demanding: the lapidary maintains the three straight sides and the three beveled sides at the same width without industrial calibration. The result is crisp edges and perfect mirror reflections on all three lateral faces.
At just 3 mm high, they are optimized for low profile settings in silver sheet: triangular tube bezel or continuous bezel following the silhouette. The deep black of obsidian creates maximum contrast with 925 silver.
How black obsidian is formed
Obsidian is volcanic glass that forms when high-silica rhyolitic lava (70–75% SiO₂) cools quickly enough to prevent crystallization. Its black color is due to small inclusions of magnetite (Fe₃O₄) within the glassy matrix. Being amorphous, it exhibits conchoidal fracture and an exceptionally vitreous surface after polishing.
What type of mounting it works for
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Flat bezel in 925 silver (earrings) — the low profile (3 mm) allows for a lightweight setting, ideal for stud or button earrings.
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Statement rings in angular bezel — the triangle is one of the most used shapes in modern ring design; oxidized silver enhances the black.
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Wire wrap — viable by wrapping the vertices with silver or copper wire for an organic finish.
Black obsidian in lapidary tradition
Obsidian has been a lapidary material since the Upper Paleolithic: its conchoidal fracture allowed for cutting edges impossible with other materials. The Aztecs called it iztli and used it in ceremonial weapons as well as divination mirrors—tezcatl—and the Romans named it obsiana in honor of General Obsius according to Pliny the Elder.
In crystal tradition, black obsidian is associated with protection and grounding — a stone of radical, nuanced clarity.
The symbolic properties attributed to minerals belong to cultural and historical traditions. They are shared for educational purposes, not as medical advice.
How to recognize genuine black obsidian
Genuine obsidian has an intense and homogeneous vitreous luster, without bubbles or turbidity. Under magnification, the conchoidal fracture (scaly spirals) distinguishes it from black onyx (quartz) whose luster is more opaque. Obsidian feels slightly colder to the touch than imitation resin and noticeably heavier.
Frequently Asked Questions
Is black obsidian dyed or treated?
No. The deep black is the natural color of the volcanic rock due to magnetite inclusions. No detectable treatment. Statement based on lapidary observation; the piece does not include formal gemological certification.
Are the two pieces in the pair exactly alike?
They share a triangular shape with chamfer and approximate dimensions (13×13×3 mm ±0.5 mm). Being hand-carved and not industrially calibrated, there may be small variations in the chamfer position. As a pair of earrings, the visual result is harmonious.
What type of mounting fits best?
Flat (3 mm), they are optimized for shallow bezels —tube bezel or soldered sheet— in 925 silver. The dimensions (13×13 mm) are suitable for button or stud earrings.
How do you care for obsidian?
Clean with a soft cloth and warm water. Avoid ultrasonic cleaners and sudden temperature changes. As it is a natural glass (5–5.5 Mohs), it can be scratched by quartz or steel. Store in a separate cloth or case. Consult our jewelry care guide.
See also: more pieces from our workshop · complete cabochon collection.
