Obsidian from USA, hand-graded by The Stone Atlas, lot XA72
Origin Glass Buttes, Oregon, USA
Mohs hardness 55.5 / 10
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Fingernail (2.5) Steel knife (5.5) Diamond (10)

Stone properties

What this stone is, geologically

Crystal system
Amorphous (volcanic glass)
Mohs hardness
5 – 5.5
Specific gravity
2.30–2.60
Refractive index
1.45–1.55
Transparency
Translucent to opaque
Durability
Moderate — chips on impact, protect edges

Volcanic glass — rhyolitic magma cooled too rapidly to crystallize. Conchoidal fracture and high silica content.

The lot

Full description

A hand-graded 4-piece lot of cabochons of obsidian from Glass Buttes, Oregon, USA, calibrated to the 23–37 mm working range. Sold as one curated lot, weighed in carats, treatments disclosed.

About this lot

Origin: Glass Buttes, Oregon, USA.

Lot: Curated 4-piece selection sold as a single unit. Total weight approximately 110 ct, hand-photographed exactly as shipped — you receive the stones in the photograph, no substitution.

Size: 23–37 mm.

Weight: 110 ct total (entire lot).

Treatment: None. 100% natural, untreated material. Disclosed on every listing — that's the Atlas standard.

Suggested use

Lapidary projects, robust everyday-wear jewellery, or studio display. Durable (Mohs 6.5+).

The Stone Atlas standard

Hand-graded in our US studio. Treatments disclosed on every listing, no exceptions. Shipped insured from the US since 1995. Returns within 14 days if the stone in hand doesn't match the listing.

Shipping & returns

  • Ships: from the US within 1–2 business days.
  • Insurance: tracked, insured for full declared value, no signature required under $1,000.
  • Returns: 30 days from delivery if the stone in hand doesn't match the listing — we cover return shipping.

Common questions

About this stone.

Is this stone treated?

No. This Obsidian is 100% natural with no heat, diffusion, dyeing, or fracture-filling treatment. We disclose treatment on every listing without exception — when it says "untreated," it is.

Where is this stone from?

This piece is from Glass Buttes, Oregon, USA.When we know the specific city or mine, we tag it on every listing. When the supplier chain is generalized, we mark it "most likely from" rather than fabricate a precise origin.

Can I see a GIA certificate?

Yes. GIA certification is available as a $95 add-on after checkout. Request it once your order ships — we'll send the stone to GIA on your behalf and forward the certificate when it arrives (typically 3–4 weeks).

What's your return policy?

Every stone comes with a 30-day inspection window. If the stone doesn't match the listing or you simply don't love it, return it within 30 days of delivery for a full refund. We cover return shipping. No restocking fees, no questions.

How long does shipping take?

Orders ship from the US within 1–2 business days. Domestic US delivery is typically 2–5 business days via USPS Priority or UPS Ground, tracked end-to-end and insured for the full declared value. International shipping is available at checkout.

Is the size in the listing exact?

Listed size for this piece: 23–37 mm. Listed weight: 110 ct ct. All sizes and weights are hand-measured. If a stone arrives outside the listed tolerance, return it within 30 days for a full refund.

Can I see this stone in different lighting before I buy?

Yes. Use the "Ask the Atlas desk" button on this page to request additional photos under daylight, lamp light, or any specific condition. We typically reply within one business day with photos attached.

What if I'm a jeweler — do you offer wholesale?

For working jewelers and lapidary studios placing recurring orders, contact us through the Atlas desk to discuss volume pricing. For one-off custom commissions, the listed prices already reflect hand-graded quality at a fair retail tier.

4.8 out of 5

11 verified buyers

What buyers say

  1. Eliza

    São Paulo Brazil

    Verified buyer 112d ago

    Real natural inclusions, just like the listing said

  2. Lucia

    Taos NM

    Verified buyer 117d ago

    Compared this to two others I bought from competitors. Clearly better saturation. Stone Atlas is now my go-to

  3. Astrid

    London UK

    Verified buyer 122d ago

    Tracking notifications were perfect. Always knew where my order was

  4. Camila

    Brussels Belgium

    Verified buyer 127d ago

    Used this for a lapidary class — perfect for what we needed

  5. Amara

    Melbourne Australia

    Verified buyer 132d ago

    Beautiful stone. Treatment was disclosed up front, exactly as the listing said. That kind of honesty is rare in this trade

  6. Sophia

    Madison WI

    Verified buyer 137d ago

    Photos don't do this justice. Even better in hand

  7. Caleb

    Portland ME

    Verified buyer 142d ago

    Beautiful. Will order again

  8. Stefan

    Barcelona Spain

    Verified buyer 147d ago

    Stone is exactly the size and weight described

  9. Léa

    Mumbai India

    Verified buyer 152d ago

    Beautiful color in natural light. Lamp light brings out a different character

  10. Hana

    Bozeman MT

    Verified buyer 157d ago

    Arrived faster than expected, tracked the whole way. The kraft box with the wax seal is a beautiful touch

  11. Khalid

    Jackson WY

    Verified buyer 162d ago

    Atlas standard is real. Treatment honesty matters