Just sold
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Origin
Kayes, Mali
Mohs hardness
6–6.5
/ 10
12345678910
Fingernail (2.5)
Steel knife (5.5)
Diamond (10)
Stone properties
What this stone is, geologically
- Crystal system
- Orthorhombic
- Mohs hardness
- 6 – 6.5
- Specific gravity
- 2.80–2.95
- Refractive index
- 1.616–1.649
- Transparency
- Translucent to opaque
- Durability
- Good — daily-wear capable
Calcium-aluminum silicate forming in basaltic cavities. The fine fibrous texture gives prehnite its waxy sheen.
The lot
Full description
A hand-graded parcel of cabochons of prehnite from Kayes, Mali, calibrated to the 7–15 mm working range. Sold by the parcel, weighed in carats, treatments disclosed.
About this lot
Origin: Kayes, Mali.
Parcel: Minimum guaranteed 10 ct total weight. Each parcel typically contains 2–4 pieces within the listed size range. You pay for guaranteed weight; piece count varies because natural material isn't uniform.
Size: 7–15 mm.
Weight: Minimum 10 ct per parcel (parent lot has 623 ct available).
Size note: Wide size variance — stones range from 7 mm to 15 mm (2.1× spread). Expect a mix of sizes rather than uniform stones. Best for cutters, lapidary projects, or mixed-jewellery use; not ideal if you need matched pairs.
Treatment: None. 100% natural, untreated material. Disclosed on every listing — that's the Atlas standard.
Suggested use
Setting in jewellery — ring bezels, pendant cabochons, statement earrings. Dome and polish are jewellery-ready.
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 Prehnite 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 Kayes, Mali.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: 7–15 mm. Listed weight: 10 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
23 verified buyers
What buyers say
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Layla
London UK
Real natural inclusions, just like the listing said
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Emma
Brussels Belgium
Compared this to two others I bought from competitors. Clearly better saturation. Stone Atlas is now my go-to
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Lucas
Melbourne Australia
Tracking notifications were perfect. Always knew where my order was
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Ruth
Madison WI
Used this for a lapidary class — perfect for what we needed
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Klara
Portland ME
Beautiful stone. Treatment was disclosed up front, exactly as the listing said. That kind of honesty is rare in this trade
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Jun
Barcelona Spain
Photos don't do this justice. Even better in hand
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Renata
Mumbai India
Beautiful. Will order again
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Zola
Bozeman MT
Stone is exactly the size and weight described
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Isabella
Jackson WY
Beautiful color in natural light. Lamp light brings out a different character
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Jonas
Vienna Austria
Arrived faster than expected, tracked the whole way. The kraft box with the wax seal is a beautiful touch
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Ines
Seoul Korea
Atlas standard is real. Treatment honesty matters
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Yuki
Portland OR
Set this into a pendant for my partner. They love it
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Mateo
Chapel Hill NC
Beautiful piece. Couldn't be happier
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Tinashe
Lyon France
The shipping was insured and tracked end-to-end. Felt safe ordering
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Noah
Reykjavik Iceland
Bought this for a custom ring setting. The depth of color is gorgeous and the size is perfect
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Abigail
Buenos Aires Argentina
Will be back for more. Quality is consistent
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Henrik
Provincetown MA
My third order from the Atlas. Consistency is excellent
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Matteo
Edinburgh UK
Worth every dollar. Real natural stone, no funny business
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Rohan
Stockholm Sweden
Origin was tagged to the city. Appreciate that level of provenance detail
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Nour
Auckland NZ
I've ordered from a lot of online gemstone dealers — this is the first time the stone matched the listing photo
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Mia
Boise ID
Highly recommend
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Owen
Toronto Canada
Smaller than I imagined but quality is high — exactly as listed
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Iris
Madrid Spain
Fast shipping, beautiful packaging, accurate listing. What more can you ask
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