The facts
What mexican Onyx actually is
Mineralogically, mexican Onyx is calcite (banded travertine) — CaCO₃, crystallising in the trigonal (aggregate) system.
The colour is caused by fe and Mn oxides in the growth banding producing honey, amber and green layers. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 1.486–1.658 (spot ~1.49–1.66), and the specific gravity sits near 2.69–2.71; cleavage is rhombohedral in the constituent crystals; the aggregate breaks irregularly.
Where mexican Onyx comes from
The recognised sources are Tecali and El Marquez, Puebla, Mexico, Baja California, Mexico, Bou Azzer region, Morocco and Pakistan (Chagai Hills).
Origin affects price in this material, so we name the locality on every quote rather than the country. "African" or "Asian" tells a buyer nothing.
How mexican Onyx is treated
Frequently dyed, most obviously in the emerald-green and cobalt-blue chess sets and bowls sold to tourists; also waxed. It is a carbonate and should never be sold as chalcedony onyx, which is silica and far harder.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What mexican Onyx is confused with
The usual confusions are Chalcedony onyx, Alabaster, Marble and Serpentine.
The separation is rarely a matter of opinion: refractive index 1.486–1.658 (spot ~1.49–1.66) and specific gravity 2.69–2.71 settle most of it in a minute, and magnification settles the rest.
What mexican Onyx is used for
Mexican Onyx is bought by carving and sculpture, decorative objects and architecture and interiors — and each of those trades wants a different form of the same material.
We quote each application in the unit that trade actually buys in, by the block, by the piece or by the square metre.
Durability and care
Mexican Onyx is 3 on the Mohs scale, with rhombohedral in the constituent crystals; the aggregate breaks irregularly cleavage.
Below about 5.5 a stone will be scratched by ordinary household dust, which is largely quartz. That does not make it unusable — it makes it a pendant, an earring or an object rather than a ring worn every day.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What mexican Onyx costs
Indicative pricing for mexican Onyx is Carvings and bookends $10–$200; large architectural slabs by the square metre.
That is a range, not a quote. Colour, size, clarity, cut and origin move the figure a long way inside it, and the only honest price is one given against a specific stone. Send us what you need and we will price it.
Questions
Is mexican Onyx treated, and how?
Frequently dyed, most obviously in the emerald-green and cobalt-blue chess sets and bowls sold to tourists; also waxed. It is a carbonate and should never be sold as chalcedony onyx, which is silica and far harder.
Where does mexican Onyx come from?
Tecali and El Marquez, Puebla, Mexico, Baja California, Mexico, Bou Azzer region, Morocco and Pakistan (Chagai Hills). Origin affects price, so we name the locality rather than the country on every quote.
Is mexican Onyx hard enough to wear every day?
Not really. At 3 on the Mohs scale it is softer than the quartz dust in ordinary household dirt, so it scratches with wear. It suits pendants, earrings and objects better than a daily ring.
How much does mexican Onyx cost?
Indicatively Carvings and bookends $10–$200; large architectural slabs by the square metre. Colour, size, clarity and origin move the price a long way within that, so treat it as a range and ask for a quote against a specific stone.
What is mexican Onyx confused with?
Most often Chalcedony onyx, Alabaster, Marble and Serpentine. A refractive index of 1.486–1.658 (spot ~1.49–1.66) and a specific gravity near 2.69–2.71 separate it quickly.
What is mexican Onyx used for besides jewellery?
carving and sculpture, decorative objects and architecture and interiors. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for mexican onyx?
Tell us the size, the quality and what it is for. We source it, photograph it and quote it — with the locality named.
Ask about mexican onyx