Buying a loose gemstone gives you independence, you get the freedom to make your own choice, your own jewelry design.
A natural 1.03 ct Emerald Cut Color-Change Sapphire, from Sri Lanka (Ceylon), completely unheated and certified by AGCL (Arctic Gem Certification & Laboratory), Report #M263506. Color-change sapphires shift hue between lighting environments — this stone displays a distinctly different color under daylight versus incandescent light (green to reddish purple, per the AGCL report), a phenomenon caused by trace vanadium in the crystal that absorbs different wavelengths under different spectral distributions. At just over 1 carat from Ceylon, unheated, this is a well-specified example of one of the most unusual optical phenomena in natural gemstones.
Expert Opinion
Ahmed Shareek's Assessment
"Genuine, lab-documented color-change sapphire is one of the rarest phenomena in the sapphire family — in my experience, on par with star sapphire for scarcity, because the vanadium chemistry needed to produce a clean shift between daylight and incandescent light rarely lines up this well. This stone's AGCL-documented change from green to reddish purple is unusually well-defined, and the fact that it's unheated matters even more here, since heat treatment is known to weaken or destroy the color-change effect entirely."
Rarity Analysis
Color-change sapphire is one of the rarest phenomena in the sapphire family, alongside star sapphire — most sapphire production never yields a stone that shifts convincingly between light sources, and this 1.03 ct stone combines that phenomenon with unheated status and a stated Ceylon origin.
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Phenomenon: This stone shows a genuine, AGCL-documented color change — green under daylight versus reddish purple under incandescent light. The effect is caused by trace vanadium in the crystal structure, which absorbs different wavelengths depending on the spectral makeup of the light source. Only a small fraction of sapphire crystals contain vanadium in the concentration and balance needed to produce a clean, visible shift, which is why color-change sapphire is considered one of the rarest sapphire phenomena alongside asterism (star sapphire).
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Color: Green (daylight) to Reddish Purple (incandescent) — a well-defined, clearly visible shift rather than a subtle tone change.
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Size: 1.03 carats — above the 1-carat threshold most buyers look for in a center stone, in a size where the color shift remains easy to see with the naked eye.
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Treatment: Unheated. This matters more for a color-change stone than for an ordinary sapphire — heat treatment can weaken or destroy the color-change effect entirely, so an unheated stone with a strong, documented shift is harder to find than an unheated stone in a standard color.
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Clarity: Eye-clean, with no visible inclusions under normal viewing — nothing to interfere with the visibility of the color shift.
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Documentation: AGCL Report #M263506 confirms no indication of heating; origin is stated as Sri Lanka (Ceylon).
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Combined effect: A genuine color-change phenomenon, unheated status, Ceylon origin, and independent lab documentation rarely converge in a single stone at this size — each factor narrows the pool of qualifying stones further.
Buying Guidance
Color-change sapphire is judged differently than a single-color stone — the quality of the shift itself, not just hue or clarity, is what separates a strong stone from an average one. A few things are worth checking before you buy.
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View it in multiple light sources: This is essential for a color-change stone — ask for photos or video showing the stone under both daylight/fluorescent light and incandescent light so you can judge the strength and cleanliness of the shift for yourself.
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Confirm the lab report matches the stone: Check that the AGCL report number, weight, and measurements correspond exactly to the stone you're purchasing.
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Ask about the degree of color change: Not all color-change sapphires shift equally strongly — some show a dramatic change, others a subtler one. Ask for a direct description of how pronounced the change is on this specific stone.
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Consider the setting: An open setting that lets light reach the pavilion will show the color-change effect more clearly than a setting that blocks light from certain angles.
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Try Before You Buy: Where possible, view the stone in person or request additional imaging under controlled light sources before committing — a phenomenon like this is best judged firsthand.
Learn More About This Gemstone
Gemstone Data — At a Glance
| Item # |
CG8412 |
| Carat Weight |
1.03 ct |
| Species / Variety |
Natural Color-Change Sapphire (Corundum) |
| Shape / Cut |
Emerald Cut |
| Dimensions |
5.80 x 4.86 x 3.72 mm |
| Color / Intensity |
Green (daylight) to Reddish Purple (incandescent), per AGCL report |
| Phenomenon |
Color Change — green (daylight) to reddish purple (incandescent), per AGCL Report #M263506 |
| Treatment |
Unheated |
| Origin |
Sri Lanka (Ceylon) |
| Clarity |
Eye-clean |
| Transparency |
Transparent |
| Hardness |
9 (Mohs) |
| Certification |
AGCL Report #M263506 |
Why Choose this 1.03 ct Unheated Ceylon Color-Change Sapphire?
Color-change sapphire in unheated quality above 1 carat from Ceylon is uncommon — the combination of the phenomenon, the treatment status, and the origin in a single stone represents a meaningful convergence of collectible attributes. The Emerald Cut at this weight is a practical format for showing the color shift in both earring/pendant and ring settings.
Key Benefits of this 1.03 ct Emerald Cut Color-Change Sapphire
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Unheated Ceylon Origin
No thermal treatment — AGCL Report #M263506 confirms no indication of heating. Heat can diminish the shift.
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Genuine Color-Change Phenomenon
The stone reads a distinctly different hue under daylight versus incandescent light — a natural optical effect.
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Above-1-Carat Size
1.03 carats — the threshold for center stone use in most standard engagement and pendant settings.
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Phenomenon Accessible to View
At this size, the color shift is clearly visible with the naked eye under different light sources.
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Durable for Daily Wear
Corundum at Mohs 9, second only to diamond.
Features
- Carat Weight: 1.03 Carats
- Gem Type: Natural Color-Change Sapphire
- Variety: Color-Change Sapphire
- Shape: Octagonal
- Cut Style: Emerald Cut
- Dimensions: 5.80 x 4.86 x 3.72 mm
- Origin: Sri Lanka (Ceylon)
- Treatment: Unheated
- Color: Green to Reddish Purple (color-change)
- Clarity: Eye-clean — no visible inclusions under normal viewing
- Hardness: 9 on the Mohs scale
- Certification: AGCL Gemstone Report #M263506
This 1.03 ct Emerald Cut Color-Change Sapphire has been hand-selected for the clarity and completeness of its color shift — the quality that distinguishes a strong color-change from a mere tone variation.
One of a Kind
This is a single natural gemstone, not a manufactured or lab-created replica — no two color-change sapphires form with identical color behavior, clarity, and internal character. Once this stone sells, it's gone; there is no duplicate. What you see documented on the AGCL report is the exact, individual stone you receive.
Care
Sapphire is exceptionally durable (Mohs 9), but a few habits keep it looking its best. Clean with warm water, mild soap, and a soft brush; avoid ultrasonic or steam cleaners if the stone is set alongside softer or treatment-sensitive materials. Store separately from other jewelry to prevent surface scratches to softer pieces, and remove the stone before swimming, exercising, or household chemical exposure. As an unheated stone, no thermal treatment stabilizes the color — normal wear is fine, but avoid sudden extreme temperature changes.
Why Customers Love This Gemstone
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Unheated Phenomenon: The color-change is entirely natural — heat can weaken this optical effect.
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Living Color: A stone that reads differently in every light source — inherently dynamic.
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Ceylon Origin: The primary source for natural color-change sapphire at the fine commercial level.
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Trusted Source: Treatment disclosed honestly and independently certified by AGCL (Report #M263506).
Owning this 1.03 ct unheated Ceylon color-change sapphire means choosing a stone whose most distinctive quality — its shift between two colors — is entirely natural and unaltered.
Perfect Uses for this 1.03 ct Color-Change Sapphire
- Distinctive engagement ring center stone
- Collector centerpiece for phenomenon gemstones
- Statement pendant — phenomenon visible in any light
- Conversation piece for fine jewelry enthusiasts
- Investment in documented natural color-change material
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