What does a GIA report certify?

A GIA report from the Gemological Institute of America independently confirms a stone's species and variety, its treatment status (heated, unheated, or otherwise treated), and in many cases its country of origin. GIA is an independent, non-profit laboratory with no financial stake in the sale.

Why do only some stones have GIA reports?

Full laboratory reports are generally reserved for larger or finer stones where the cost of certification is proportionate to the stone's value. Smaller or more affordable stones may still be entirely natural and accurately described without a formal GIA report.

Does a GIA report guarantee a stone is unheated?

No - a GIA report states the treatment status as observed, which may be heated or unheated. We disclose treatment status plainly on every product page regardless of what the report shows, so buyers can filter for unheated stones specifically if that matters to them.

What makes this 2.01 ct color-change sapphire a unique gemstone?

This 2.01 ct sapphire is a true color-change stone — it shifts from greenish-blue under daylight/fluorescent light to purple under incandescent light, a genuine optical phenomenon that is much rarer than a single-hue sapphire of the same size.

What causes the color-change effect in this sapphire?

The color change is a natural optical property caused by how the stone's trace elements absorb different wavelengths of light — it is not a treatment or coating, and the GIA report confirms the stone is unheated and untreated.

What are the care instructions for this color-change sapphire?

Clean it regularly with mild soap and warm water, avoid harsh chemicals, and store it separately from other jewelry to prevent scratches.

What does the GIA report confirm about this sapphire?

GIA Report #1236949156 confirms the stone's weight (2.01 ct), dimensions, color change from greenish-blue to purple, transparency, and no indications of heating; geographic origin was not requested for this report.

Is this color-change sapphire suitable for daily wear?

Yes, corundum's hardness (9 on the Mohs scale) makes this sapphire suitable for both everyday wear and special occasions.

2.01 ct cushion Color change Sapphire — greenish-blue in daylight, unheated, GIA certified

2.01 ct cushion color-change sapphire — color shift from greenish-blue to purple demonstrated

2.01 ct cushion Color change Sapphire showing cut detail and blue-green to purple color shift — unheated

2.01 ct cushion Color change Sapphire — natural, unheated, eye-clean

2.01 ct cushion Color change Sapphire — rare greenish-blue to purple phenomenon stone, unheated

2.01 ct cushion color-change sapphire — GIA certified unheated phenomenon stone

2.01 ct cushion Color change Sapphire in natural light — unheated phenomenon stone, GIA report

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CG8355

2.01 ct Natural Unheated Color-Change Sapphire – Cushion Cut | GIA Certified

¥351,700 JPY

1カラットあたり： ¥174,975

ルースをお選びいただくことで、石もジュエリーのデザインも、ご自身の思いのままにお決めいただけます。

カットスタイル	ファセットカット
宝石の種類	サファイア
重量（ct）	2.01
処理	無処理
産地	マダガスカル
クラリティ	微小な内包物（当店評価）
カラー	カラーチェンジ
カラーの詳細	This stone exhibits a change of color when viewed under daylight or fluorescent vs incandescent light.
色の濃さ	インテンス
シェイプ	レクタングルクッション
サイズ（mm）	7.17 x 5.80 x 4.81
カット	Mixed Brilliant
鑑別書	GIA

2.01 carat rectangular cushion-cut color-change sapphire, natural and completely unheated, measuring 7.17 × 5.80 × 4.81 mm. The stone shifts from a saturated greenish-blue under daylight and fluorescent light to a clear purple under incandescent light — a well-defined two-color response that qualifies as a true color-change phenomenon. The shift is immediately visible when moving the stone between light sources. No heat treatment or any other enhancement of any kind; the color change is the stone's own natural property. Accompanied by GIA Report #1236949156 confirming natural origin, weight, dimensions, and unheated status.

Expert Opinion

"What makes this stone worth stopping for is the phenomenon itself," says Ahmed Shareek, gemologist at Crescent Gems. "This is a true, well-defined color-change sapphire — a saturated greenish-blue in daylight or fluorescent light that shifts to a clear purple under incandescent light. That's not a subtle drift in tone; it's two distinct colors in one stone, and it's completely natural and unheated. Genuine color-change corundum with this strong a response is something you don't come across often."

Rarity Analysis

True color-change phenomenon: Genuine color-change sapphire is rare in the gem market. The specific trace-element combination — typically vanadium — that produces a strong, well-defined two-color response in corundum under different light sources is uncommon; it's a much less frequent occurrence than the color-change effects seen in garnet or the classic alexandrite response in chrysoberyl.
Strength and clarity of the shift: This stone shows a well-defined two-color response, not a partial or muddy transition. A clean, unambiguous shift between greenish-blue and purple is itself a quality and rarity marker — many color-change stones on the market show only a faint or inconsistent shift.
Unheated and untreated: This sapphire has never been heated. Heat treatment can damage or alter the trace-element structure responsible for color change, so natural material that displays this phenomenon without any enhancement is especially valued.
Clarity: Minor inclusions under 10× in our own assessment — an honest, eye-clean grade rather than a flawless one. We note this plainly rather than overselling it.
Independent documentation: Accompanied by GIA Report #1236949156, confirming natural origin, weight, dimensions, and unheated status from an independent laboratory.
Combined effect: A genuine, strongly defined color-change phenomenon in an unheated natural sapphire, backed by GIA documentation, places this stone in a distinctly small category of gemstones — most sapphires show no color-change effect at all, and those that do rarely display it this clearly.

Buying Guidance

View the stone under both daylight (or fluorescent) light and incandescent light before buying. The entire value of this gem lies in the shift itself, so confirm you like both the greenish-blue daylight color and the purple incandescent color — not just one of the two.
Verify unheated, natural color-change status through an independent lab report rather than taking a listing's word for it. Color-change effects can sometimes be imitated, induced, or enhanced in lesser stones, so third-party confirmation matters here more than with a single-color sapphire.
Keep in mind the origin listed, Madagascar, is seller-stated rather than explicitly confirmed on the GIA report, which documents natural origin, weight, dimensions, and unheated status but does not certify country of origin.
Judge clarity honestly: in our own assessment this stone has minor inclusions under 10× — eye-clean beauty, not a flawless stone — and that distinction should factor into your expectations at this price point.
Try Before You Buy: Because this stone's entire appeal rests on the light-to-light transformation, we recommend examining it in person or under multiple lighting setups whenever possible, so you can be certain both color states work for you before committing.

Learn More About This Gemstone

Gemstone Data — At a Glance

Item #	CG8355
Carat Weight	2.01 ct
Species / Variety	Natural Color-Change Sapphire (Corundum)
Shape / Cut	Rectangular Cushion, Mixed Brilliant
Dimensions	7.17 × 5.80 × 4.81 mm
Color / Intensity	Saturated greenish-blue (daylight/fluorescent) to purple (incandescent)
Phenomenon	True color-change (greenish-blue to purple)
Treatment	None — unheated and untreated
Origin	Madagascar — seller-stated
Clarity	Minor inclusions under 10× — our own assessment; GIA colored-stone reports carry no clarity grade
Transparency	Transparent
Hardness	9 (Mohs)
Certification	GIA Report #1236949156

Features

SKU: CG8355
Carat Weight: 2.01 carats
Variety: Color-Change Sapphire
Shape: Rectangular Cushion
Cutting Style: Mixed Brilliant (brilliant crown, modified step cut pavilion)
Dimensions: 7.17 × 5.80 × 4.81 mm
Gem Type: Natural Color-Change Sapphire
Origin: Madagascar
Treatment: None — unheated and untreated (no indications of heating)
Color: Greenish-blue (daylight / fluorescent) to purple (incandescent)
Transparency: Transparent
Clarity: Minor inclusions under 10× — our own assessment, not a GIA grade
Certification: GIA Report #1236949156
Hardness: 9 on the Mohs scale

Care

Clean with lukewarm water and mild soap using a soft brush
Store separately to avoid surface contact
Remove before heavy physical activity
Avoid ultrasonic or steam cleaners

One of a Kind

This is a single natural gemstone, not a manufactured or lab-created replica — no two sapphires form with identical color, inclusions, and internal character, and true color-change stones like this one are especially uncommon. Once this stone sells, it's gone; there is no duplicate. What you see documented on the GIA report is the exact, individual stone you receive.

What’s included with this Color-Change Sapphire

GIA Report #1236949156
Gemstone packed in a gem sleeve

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