UV Stick Agate from Tanzania, hand-graded by The Stone Atlas, lot XA53
Origin Mwadui, Tanzania
Mohs hardness 67 / 10
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Fingernail (2.5) Steel knife (5.5) Diamond (10)

Stone properties

What this stone is, geologically

Crystal system
Trigonal (microcrystalline silica)
Mohs hardness
6 – 7
Specific gravity
2.58–2.64
Refractive index
1.530–1.539
Transparency
Translucent to opaque
Durability
Robust — everyday-wear capable

Cryptocrystalline silica precipitating in vesicles and fractures. Banding records mineral-rich groundwater cycles.

The lot

Full description

A hand-graded 1-piece lot of cabochons of uv stick agate from Mwadui, Tanzania, calibrated to the 32 mm working range. Sold as one curated lot, weighed in carats, treatments disclosed.

About this lot

Origin: Mwadui, Tanzania.

Lot: Curated 1-piece selection sold as a single unit. Total weight approximately 109 ct, hand-photographed exactly as shipped — you receive the stones in the photograph, no substitution.

Size: 32 mm.

Weight: 109 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 UV Stick Agate 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 Mwadui, Tanzania.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: 32 mm. Listed weight: 109 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.

4.6 out of 5

27 verified buyers

What buyers say

  1. Asher

    Asheville NC

    Verified buyer 127d ago

    Real natural inclusions, just like the listing said

  2. Soren

    Park City UT

    Verified buyer 132d ago

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

  3. Mei

    Munich Germany

    Verified buyer 137d ago

    Tracking notifications were perfect. Always knew where my order was

  4. Valentina

    Kyoto Japan

    Verified buyer 142d ago

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

  5. Sarah

    Marrakech Morocco

    Verified buyer 147d ago

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

  6. Mason

    Bend OR

    Verified buyer 152d ago

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

  7. Maya

    Paris France

    Verified buyer 157d ago

    Beautiful. Will order again

  8. Eleni

    Helsinki Finland

    Verified buyer 162d ago

    Stone is exactly the size and weight described

  9. Aiko

    São Paulo Brazil

    Verified buyer 2d ago

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

  10. Diego

    Taos NM

    Verified buyer 7d ago

    Color is a touch lighter than the listing photo shows, but still lovely

  11. Adwoa

    London UK

    Verified buyer 12d ago

    Took a few days longer to arrive than I expected, but worth the wait

  12. Ava

    Brussels Belgium

    Verified buyer 17d ago

    Good stone, small surface character not really visible in the photos

  13. Wyatt

    Melbourne Australia

    Verified buyer 22d ago

    Nice piece, slightly more inclusions than I expected — but consistent with the listed grade

  14. Pieter

    Madison WI

    Verified buyer 27d ago

    Slightly smaller than I imagined but the quality is great

  15. Giulia

    Portland ME

    Verified buyer 32d ago

    Beautiful stone, would have liked one or two more detailed photos before ordering

  16. Carlos

    Barcelona Spain

    Verified buyer 37d ago

    Color is a touch lighter than the listing photo shows, but still lovely

  17. Kofi

    Mumbai India

    Verified buyer 42d ago

    Took a few days longer to arrive than I expected, but worth the wait

  18. Ethan

    Bozeman MT

    Verified buyer 47d ago

    Good stone, small surface character not really visible in the photos

  19. Evelyn

    Jackson WY

    Verified buyer 52d ago

    Nice piece, slightly more inclusions than I expected — but consistent with the listed grade

  20. Lukas

    Vienna Austria

    Verified buyer 57d ago

    I've ordered from a lot of online gemstone dealers — this is the first time the stone matched the listing photo

  21. Hugo

    Seoul Korea

    Verified buyer 62d ago

    Highly recommend

  22. Kenji

    Portland OR

    Verified buyer 67d ago

    Smaller than I imagined but quality is high — exactly as listed

  23. Yasmin

    Chapel Hill NC

    Verified buyer 72d ago

    Fast shipping, beautiful packaging, accurate listing. What more can you ask

  24. Olivia

    Lyon France

    Verified buyer 77d ago

    Bought as a 10-year anniversary gift. Stunning

  25. Henry

    Reykjavik Iceland

    Verified buyer 82d ago

    The 30-day inspection window made me comfortable ordering at this price point. Didn't need to use it

  26. Cora

    Buenos Aires Argentina

    Verified buyer 87d ago

    Exactly what I needed for my project

  27. Anja

    Provincetown MA

    Verified buyer 92d ago

    Working on a custom necklace; this is the centerpiece