The facts
What obsidian actually is
Obsidian is classified as volcanic glass, with the composition Approximately 70% SiO₂. It crystallises in the amorphous system.
Colour comes from iron and magnetite; sheen from gas bubbles or crystallites, which is also what a laboratory looks at when it is asked whether a colour is natural.
Refractive index 1.450–1.520. Specific gravity around 2.30–2.60. Cleavage: none — conchoidal fracture. Those three numbers separate it from most of what imitates it.
Where obsidian comes from
Obsidian is produced at Michoacán, Mexico, Oregon, USA, Armenia and Iceland.
The locality is part of the description, not a footnote — two stones of the same weight from two of these places are not the same stone.
Is obsidian treated?
None. Manufactured glass is sold as obsidian.
That makes disclosure simple: there is nothing to declare. It also means a seller offering a "treated" version of this material is offering something else.
What obsidian is confused with
In the trade obsidian is most often mistaken for, or substituted by, Manufactured glass, Jet, Black onyx or Schorl.
The separation is rarely a matter of opinion: refractive index 1.450–1.520 and specific gravity 2.30–2.60 settle most of it in a minute, and magnification settles the rest.
What obsidian is used for
Demand for obsidian comes from decorative objects, jewellery, carving and sculpture, wellness and body care and surgical blades, which is why one price per carat never covers it.
We quote each application in the unit that trade actually buys in, by the piece, by the carat or by the block.
Durability and care
Hardness 5–5.5; cleavage none — conchoidal fracture. That combination decides what it can safely be set into.
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 obsidian costs
As a guide, obsidian trades around $0.10–5/ct.
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 obsidian treated?
None. Manufactured glass is sold as obsidian.
Where does obsidian come from?
Michoacán, Mexico, Oregon, USA, Armenia and Iceland. Origin affects price, so we name the locality rather than the country on every quote.
Is obsidian hard enough to wear every day?
Not really. At 5–5.5 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 obsidian cost?
Indicatively $0.10–5/ct. 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 obsidian confused with?
Most often Manufactured glass, Jet, Black onyx and Schorl. A refractive index of 1.450–1.520 and a specific gravity near 2.30–2.60 separate it quickly.
What is obsidian used for besides jewellery?
decorative objects, carving and sculpture, wellness and body care and surgical blades. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for obsidian?
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 obsidian