Black onyx tumbled stones, 31-37 mm, with intense, uniform black tone, tumbled in a lapidary barrel. Satin surface with sparkles in the more convex areas.
Piece details
| Mineral |
Black onyx (black chalcedony, a variety of microcrystalline quartz) |
| Dimensions |
31-37 mm · Weight: 16-20 g · Freeform ±0.5 mm |
| Shape and back |
Tumbled, rounded freeform, convex back |
| Finish |
Barrel polished (satin-glossy) |
| Hardness |
6.5-7 Mohs — resistant to everyday wear |
| Origin |
Material acquired in lapidary wholesale market |
| Treatment |
No detectable treatment. Commercial black onyx may have received standard carbon impregnation in the industry. Statement based on lapidary observation; the piece does not include formal gemological certification. |
| Piece type |
Standard tumbled stone — each unit varies slightly in shape |
These particular tumbled stones
Black onyx has a visual constant rarely surpassed in the mineralogical collection: the black is absolute. There are no contrasting veins or translucency.
The barrel finish of this lot is satin with a concentration of shine in the more convex areas.
How black onyx is formed
Onyx is chalcedony — microcrystalline quartz — that precipitates in parallel layers within hydrothermal cavities. When the color layer is uniform black instead of banded, it is called black onyx.
Uses of black onyx tumbled stones
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Collection and decoration — absolute black creates effective contrast with light-colored minerals. Ideal for mineralogical compositions in trays or frames.
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Wire wrap — the uniform surface allows for a clean hold with 20 gauge wire; the 31-37 mm size is suitable for wrapped pendants.
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Carry stone / palmstone — the weight (16-20 g) and smooth finish make these tumbled stones a comfortable hand piece.
Onyx in lapidary tradition
Onyx was widely used in antiquity for seals, cameos, and goldsmith pieces.
In crystal tradition, black onyx is associated with protection, grounding, and inner strength. It is described as a stone of containment, associated with concentration and stability in moments of dispersion.
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 black onyx
Genuine onyx is cold to the touch and gradually warms with hand heat. Under 10× magnification, it shows a fine microcrystalline texture with no bubbles.
Frequently asked questions
Is black onyx dyed?
Commercial black onyx frequently receives carbon impregnation treatment to homogenize the color. This process is standard in the industry and does not affect durability.
Is it suitable for wire wrap or artisanal jewelry?
Yes. The smooth surface and hardness of 6.5-7 protect it from usual wear. The 31-37 mm size is suitable for pendants in 20-22 gauge wire wrap.
Does the shape vary between units?
Yes. Barrel polishing generates individual freeforms. The 31-37 mm dimensions are the range of the lot; each unit will have its characteristic shape within that interval.
What differentiates onyx from jet?
Jet is lignite (fossilized organic carbon): light, warm to the touch, hardness 2.5-4, and resinous luster. Onyx is chalcedony (SiO₂): denser, cold to the touch, hardness 6.5-7, and vitreous luster. The weight in hand distinguishes them immediately.
How much does each unit weigh?
Between 16 and 20 g depending on the piece, corresponding to the 31-37 mm size range. If you need a very specific weight for a piece of jewelry, contact us for manual selection.
How to care for black onyx?
Clean with a soft damp cloth. Avoid acids and ultrasonic cleaners that can affect the surface treatment. For more information: mineral care guide.
More about onyx: properties, meaning, and uses. See also: tumbled minerals · lapidary cabochons.
