Blue Star Sapphire from Madagascar, hand-graded by The Stone Atlas, lot XA44
Origin Andilamena, Madagascar
Mohs hardness 9 / 10
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Fingernail (2.5) Steel knife (5.5) Diamond (10)

Stone properties

What this stone is, geologically

Crystal system
Trigonal (corundum)
Mohs hardness
9
Specific gravity
3.95–4.05
Refractive index
1.762–1.778
Transparency
Transparent to translucent
Durability
Exceptional — second only to diamond

Aluminum oxide crystallized at high temperature in metamorphic and igneous environments. Asterism comes from oriented rutile inclusions.

The lot

Full description

A hand-graded parcel of cabochons of blue star sapphire from Andilamena, Madagascar, calibrated to the 5–10 mm working range. Sold by the parcel, weighed in carats, treatments disclosed.

About this lot

Origin: Andilamena, Madagascar.

Parcel: Minimum guaranteed 10 ct total weight. Each parcel typically contains 5–8 pieces within the listed size range. You pay for guaranteed weight; piece count varies because natural material isn't uniform.

Size: 5–10 mm.

Weight: Minimum 10 ct per parcel (parent lot has 108 ct available).

Size note: Wide size variance — stones range from 5 mm to 10 mm (2.0× 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 Blue Star Sapphire 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 Andilamena, Madagascar.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: 5–10 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.

4.6 out of 5

7 verified buyers

What buyers say

  1. Kenji

    Lexington KY

    Verified buyer 37d ago

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

  2. Yasmin

    Florence Italy

    Verified buyer 42d ago

    Highly recommend

  3. Olivia

    Taipei Taiwan

    Verified buyer 47d ago

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

  4. Henry

    Asheville NC

    Verified buyer 52d ago

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

  5. Cora

    Park City UT

    Verified buyer 57d ago

    Bought as a 10-year anniversary gift. Stunning

  6. Anja

    Munich Germany

    Verified buyer 62d ago

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

  7. Anjali

    Kyoto Japan

    Verified buyer 67d ago

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