Buying a loose gemstone gives you independence, you get the freedom to make your own choice, your own jewelry design.
A natural 1.55 carat blue sapphire in a cushion cut, from Sri Lanka (Ceylon), heat treated and documented on AGCL Report #M2513590. Ceylon cushion blue sapphire is the most historically resonant format in sapphire jewelry — the Princess of Wales ring that brought sapphire into global engagement ring consciousness was a 12-carat Ceylon cushion blue, and the shape has defined the category ever since. At 1.55 carats, this stone sits in the practical center stone range for engagement rings, with the cushion geometry deepening the Ceylon blue saturation across the face.
Expert Opinion
Ahmed Shareek's Assessment
"This 1.55 ct cushion shows exactly what Ceylon blue should look like in this cut — the larger cushion facets pull the saturation across the whole face rather than concentrating it at the culet, and at this size it works as a genuine center stone rather than an accent. The heat treatment is disclosed and standard practice for this color, so nothing about how the color got here is hidden."
Rarity Analysis
Blue is the most widely produced sapphire color, so the case for this stone rests on the specific combination below, not on color alone.
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Color: Blue is the most available sapphire body color on the market, but even within blue, an even, medium-to-deep saturation that reads well face-up — as this stone does in cushion cut — is not the norm at every price point.
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Size: At 1.55 carats, this stone sits above the sub-1-carat sizes that make up most of the clean, well-cut Ceylon blue supply, while staying well short of the pricing jump that comes with 2+ carat stones.
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Cut: The rectangular cushion cut is the same format associated with the world's best-known blue sapphire engagement ring, yet most rough is still cut into rounds and ovals for better yield, so well-proportioned cushions are comparatively harder to source.
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Treatment: Heat treatment is the standard, widely accepted practice for the great majority of commercial blue sapphire on the market today — it is not a rarity factor for this stone, and we're not presenting it as one. It's disclosed here because that's the honest baseline, not an exception.
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Documentation: AGCL Report #M2513590 independently confirms this stone's identity, weight, and treatment status in writing — paperwork that a meaningful share of comparably priced sapphires on the market are sold without.
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Combined effect: No single factor here makes this stone hard to replace. It's the combination — Ceylon-origin blue, a well-executed cushion cut, a practical center-stone carat weight, and independent lab documentation — that narrows the field of real equivalents.
Buying Guidance
A few practical points to weigh before purchasing this specific stone:
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Check it under more than one light source. Cushion cuts mix large flash facets with tighter scintillation patterns, and how open or closed the color reads can shift noticeably between daylight, indoor incandescent, and jewelry-counter LED lighting.
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Confirm mounting fit before ordering a setting. At 6.38 x 5.65 x 4.74 mm, this stone falls within the range most standard cushion-cut prong and halo mountings are built for, but always confirm the setting's stated stone size against these exact dimensions before committing.
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Always confirm treatment disclosure when comparison shopping. A large share of blue sapphire sold online is heat treated but not every listing says so plainly — this stone's treatment is stated outright here and documented on its AGCL report, and any stone you compare it against should offer the same clarity.
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Weigh availability against the specifics you actually want. Given the combination covered in the Rarity Analysis above — Ceylon origin, cushion format, and this carat weight together — a close match on all three at once won't be a given if you wait.
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Use the Try Before You Buy option if you would like to see the stone in hand before finalizing the purchase.
Learn More About This Gemstone
Gemstone Data — At a Glance
| Item # |
CG8350 |
| Carat Weight |
1.55 ct |
| Species / Variety |
Natural Blue Sapphire (Corundum) |
| Shape / Cut |
Rectangular Cushion, Mixed Brilliant |
| Dimensions |
6.38 x 5.65 x 4.74 mm |
| Color / Intensity |
Blue |
| Phenomenon |
None |
| Treatment |
Heat Treated |
| Origin |
Sri Lanka (Ceylon) — store's own assessment; not addressed by the AGCL report |
| Clarity |
Eye Clean |
| Transparency |
Transparent |
| Hardness |
9 (Mohs) |
| Certification |
AGCL Report #M2513590 |
Features
- SKU: CG8350
- Carat Weight: 1.55 Carats
- Variety: Blue Sapphire
- Dimensions: 6.38 x 5.65 x 4.74 mm
- Shape: Rectangular Cushion
- Cut Style: Mixed Brilliant
- Origin: Sri Lanka (Ceylon)
- Treatment: Heat Treated
- Color: Blue
- Clarity: Eye Clean — no visible inclusions under normal viewing
- Transparency: Transparent
- Hardness: 9 on the Mohs scale
- Certification: AGCL Report #M2513590
One of a Kind
This is a single natural gemstone, not a lab-created or manufactured stone — no two are exactly alike. Once sold, this particular 1.55 ct blue sapphire will not be available again.
Care
Clean with warm soapy water and a soft brush. Avoid ultrasonic cleaners and harsh chemicals, and store separately from harder or abrasive materials to prevent scratching.
This 1.55 ct cushion Ceylon blue sapphire has been hand-selected for the richness and evenness of its blue — the characteristic most responsible for the lasting demand for this configuration. Documented on AGCL Report #M2513590, its heat treatment is standard practice for this color and fully disclosed.
Perfect Uses
- Engagement ring center stone
- Custom pendant solitaire
- Three-stone ring center stone
- September birthstone jewelry
- Anniversary gift at the fine jewelry level
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