Quick Answer: Black onyx is the solid black form of chalcedony, with a Mohs hardness of 7, according to Minerals.net. The same source says black onyx is often dyed, while the banded black and white form is usually natural. Before you buy onyx jewelry, ask what the beads are, whether they are treated and how the piece closes. Akitai's onyx bracelet is a stretch bracelet with matte beads.
Black onyx is easy to like and easy to mix up with other black stones. This guide is for buying, not for meaning. It covers what the stone is, what to ask about dye, what gets mistaken for it, how matte and polished beads differ and how to look after the piece. For what onyx is traditionally said to stand for, see the guide to onyx meaning. The one product here is Akitai's onyx charm bracelet, covered near the end.
It is a solid black chalcedony. Minerals.net (checked October 2026) gives the most accepted definition of onyx as a solid black chalcedony, or a banded black and white chalcedony, and lists its hardness as 7 on the Mohs scale. It says onyx is usually cut into cabochons and beads, used mostly in bracelets, necklaces, earrings and rings, and has been used in jewelry and carving since antiquity.
The word is used loosely, though. Minerals.net notes that "onyx" is occasionally applied to any engraved stone with a solid color base, or to any banded gemstone with parallel bands. So a listing that says onyx jewelry can mean more than one thing, and the plain name "black onyx" is the solid black form.
Often, according to Minerals.net. It says black onyx is often dyed, and that the banded black and white form is usually natural and not dyed. Treatment is a fair question to put to any seller, and the answer tells you more than the color does.
This guide makes no claim about Akitai's beads either way. The product page for the onyx bracelet names the stone and describes the beads as matte black. It does not describe any treatment.
Several black materials can look alike. Minerals.net lists the look-alikes below, along with one false name that is a different material.
| Material | What Minerals.net says |
|---|---|
| Black diamond | Onyx is much softer and less lustrous |
| Jet | Onyx is much harder |
| Hematite | Onyx lacks its metallic luster |
| Melanite garnet, schorl tourmaline | Can be very hard to tell apart from onyx |
| Onyx marble (Mexican onyx) | Banded travertine or tufa, a different material; can be polished and dyed |
The practical point is that a name on a listing does not settle what a bead is. Ask the seller to name the material, and be wary of a listing that only says "black stone".
Either works, and it is a style choice. Polished beads have a glossy surface that catches light. Matte beads have a flat, soft finish. Minerals.net lists the stone's luster as vitreous, a glassy shine, which is what a polished bead shows off. A matte bead reads quieter and sits easily with casual clothes, while a polished one tends to look dressier.
Black goes with most colors, so the finish matters more than the shade. If you stack bracelets, one dark matte strand can calm down a busy set. The post on stacking charm bracelets has ideas for combining them.
Treat it like any beaded jewelry: keep it dry and put it on last. Akitai's Warranty page says to keep jewelry dry, away from perfume, lotion and cleaning agents, and to store it in a cool, dry place out of direct sunlight, with a pouch or a soft cloth to prevent scratches.
A hardness of 7 is a number about the mineral, not a promise about a bracelet. Beads can still be knocked, and the cord on a stretch bracelet wears like any cord. Take the bracelet off before washing your hands or doing rough work. For a table that compares the hardness of the other stones in Akitai's range, see the guide to beaded bracelets for women.
One does. Akitai's onyx charm bracelet is one example, and since Akitai is the brand behind this site, it is our own product. Its product page describes a handmade stretch bracelet with matte black onyx beads and two tassels, made in Thailand. It lists an inner length of about 6.2 inches that stretches up to 7 inches, and says the bracelet comes in a recyclable gift box. The other three bracelets in the range use different stones and are in the charm bracelet collection.
If you are buying onyx as a present, the Christmas jewelry gifts guide covers how to choose a bracelet for someone else.
It is a solid black chalcedony with a Mohs hardness of 7, per Minerals.net. It is usually cut into cabochons and beads.
Often, but ask. Onyx names are also used for other materials, such as onyx marble, which Minerals.net describes as banded travertine or tufa. A seller should be able to name the material.
Onyx can be solid black or banded black and white. Black onyx is the solid black form. Minerals.net says the banded form is usually natural, while black onyx is often dyed.
The stone is 7 on the Mohs scale. That describes the mineral, so a bead can still chip if it is struck hard, and a stretch cord can still wear.
People link onyx with different ideas, which the onyx meaning guide sets out. These are traditional beliefs, not medical facts, and a stone is not a treatment for any condition. Wikipedia says there is no peer-reviewed scientific evidence that crystal healing has any effect.
Yes, with basic care. Keep it dry, put it on after perfume and lotion, and store it where it will not be knocked against other pieces.
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