identified this stone yet
White Sapphire
| Hardness | 9 |
| Specific gravity | 4.00 |
| Refractive index | 1.762-1.770 |
| Crystal system | 六方晶系（三方晶系） |
Colorless to near-colorless, sometimes with a faint blue, yellow, or smoky undertone visible against a white background. The finest material is bright white with no perceptible tint.
- Silk: fine rutile needles in three crystallographic directions
- nclusions
- nclusions (mineral grains, zircon halos in iron-rich stones)
- Generally eye-clean in commercial-grade material
- Doubly refractive, uniaxial negative
- Refractive index 1.762–1.770
- 0.008–0.009
- Specific gravity 4.00
- 0.018 — much lower than diamond (0.044), the chief optical 'tell' separating white sapphire from diamond
- 01Refractometer reading of 1.76–1.77 — instantly separates white sapphire from diamond (RI 2.42), CZ (RI 2.15), moissanite (RI 2.65), and quartz (RI 1.54–1.55)
- 02Specific gravity 4.00 — well above quartz (2.65) and diamond (3.52), below CZ (5.6–6.0)
- 03nclusions visible at 10× under immersion indicate Verneuil flame-fusion synthetic
- 04Lower than diamond — visibly less rainbow fire, more 'glassy white' brilliance
- Mohs 9 — extremely durable, second-hardest natural gem after diamond; safe for daily wear in any setting
- Safe to ultrasonic and steam cleaning unless the stone is fracture-filled or heavily included
- Stable to all normal jeweler's chemicals
Several thousand yen per carat for commercial Madagascan material up to ¥50,000–80,000/ct for fine eye-clean Sri Lankan stones in the 1–2 ct range. Significantly cheaper than diamond at every quality grade, and the price gap widens above 2 ct.
Note: Standard heat treatment to drive off residual color is universal and accepted; disclosure is rarely contentious. The chief market discriminator is natural versus Verneuil flame-fusion synthetic — visually indistinguishable to the unaided eye but separable by characteristic curved striae and gas-bubble inclusions under 10× magnification. Lab reports are inexpensive and standard practice for engagement-ring center stones.
White sapphire is colorless corundum (Al₂O₃) — chemically identical to ruby and blue sapphire but lacking the chromium, iron, and titanium chromophores that color its kin. Mohs 9, just below diamond, with refractive index 1.76–1.77 and specific gravity 4.00. Most commercial white sapphire is produced by heating pale-blue or pale-yellow corundum to drive off the residual tint and yield a clean colorless gem. Sri Lanka and Madagascar dominate the supply, and both natural and Verneuil flame-fusion synthetic colorless corundum are widely traded.
Origins
aceted goods and rough for the global trade. Tanzania (Umba Valley, Tunduru), Myanmar (Mogok), and Montana also contribute. Most commercial stones are heat-treated to drive off pale blue, yellow, or grey tints.
History
Colorless sapphire was prized in medieval Christendom as sapphirus albus — the ecclesiastical stone of cardinals and bishops, valued for its purity and durability. From the 1990s onward, as De Beers' diamond pricing climbed and consumer interest in ethical alternatives grew, white sapphire returned to prominence as the most durable affordable diamond substitute. Boutique designers including Brilliant Earth, Catbird, and Anna Sheffield popularized the stone for ethical engagement rings through the 2010s.
Lore & symbolism
Associated since antiquity with celestial wisdom and clarity of thought, sapphirus albus was used in episcopal rings as a symbol of priestly purity and spiritual office. Modern marketing retains September's birthstone association from blue sapphire and positions white sapphire as the stone of mental clarity, focus, and decisive judgment.
Tools to confirm this stone
Tools that help confirm White Sapphire. Tap any item to jump to the matching section on the gem tools page.
- 最終確認日
- 2026年4月28日
- 参 考 文 献
- Gem Encyclopedia／ GIA (Gemological Institute of America)
- 宝石鑑別基準／ 中央宝石研究所 (CGL)
- Mineral & Gem Database／ Mindat.org / Gemdat.org
- 宝石学入門／ 全国宝石学協会
本ページの物性値（屈折率・比重・硬度・結晶系等）は、上記の権威ある一次資料を相互参照して編集しています。最新の鑑別研究の進展により値が更新される場合があります。