Phosphosiderite from Zimbabwe, hand-graded by The Stone Atlas, lot XA75
Origin Bikita, Zimbabwe
Mohs hardness 3.54.5 / 10
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Fingernail (2.5) Steel knife (5.5) Diamond (10)

Stone properties

What this stone is, geologically

Crystal system
Orthorhombic / triclinic (phosphate group)
Mohs hardness
3.5 – 4.5
Specific gravity
2.5–2.8
Refractive index
1.55–1.69
Transparency
Translucent to opaque
Durability
Soft — display and pendant use preferred

Hydrated phosphates from secondary deposits in iron-rich or aluminum-rich host rocks.

The lot

Full description

A hand-graded cabochon of phosphosiderite from Bikita, Zimbabwe, calibrated to the 18 mm working range. Sold as a single piece, weighed in carats, treatments disclosed.

About this lot

Origin: Bikita, Zimbabwe.

Format: One specific cabochon, weighing approximately 20 ct, hand-graded from a parent lot of 1012 ct. Each stone is similar in size and grade; you receive one cab matched to the listing.

Size: 18 mm.

Weight: ~20 ct per piece.

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

Suggested use

Lapidary work, custom jewellery settings, or studio display.

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 Phosphosiderite 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 Bikita, Zimbabwe.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: 18 mm. Listed weight: 20 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

9 verified buyers

What buyers say

  1. Lucia

    Mumbai India

    Verified buyer 37d ago

    Real natural inclusions, just like the listing said

  2. Astrid

    Bozeman MT

    Verified buyer 42d ago

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

  3. Camila

    Jackson WY

    Verified buyer 47d ago

    Tracking notifications were perfect. Always knew where my order was

  4. Amara

    Vienna Austria

    Verified buyer 52d ago

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

  5. Sophia

    Seoul Korea

    Verified buyer 57d ago

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

  6. Caleb

    Portland OR

    Verified buyer 62d ago

    Slightly smaller than I imagined but the quality is great

  7. Stefan

    Chapel Hill NC

    Verified buyer 67d ago

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

  8. Léa

    Lyon France

    Verified buyer 72d ago

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

  9. Hana

    Reykjavik Iceland

    Verified buyer 77d ago

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