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Aquamarine
| Hardness | 7.5-8 |
| Specific gravity | 2.72 |
| Refractive index | 1.577-1.583 |
| Crystal system | 六方晶系 |
Pale sky blue, sea blue, and the deeply saturated 'Santa Maria' blue (a Brazilian trade name now applied to any top-color stone). Pure blue is more valuable than greenish blue in modern markets, though the opposite was true historically.
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- Generally exceptionally clean for a colored stone
- Doubly refractive, uniaxial negative
- Distinct dichroism: blue and colorless to pale blue
- 01Long are diagnostic of natural beryl
- 02Strong dichroism distinguishes from blue topaz (weak dichroism) and blue spinel (singly refractive)
- 03RI 1.567–1.590 and SG 2.68–2.74 are characteristic
- Durable for daily wear
- Safe to ultrasonic and steam unless heavily included
- Avoid prolonged heat — can be partially reversed
From $30/ct for light commercial material up to $1,500/ct for top Santa Maria color in clean larger stones.
Note: Heat treatment is universal and accepted. Pure deep blue (Santa Maria color) commands a significant premium over greenish material. Synthetic aquamarine exists but is uncommon in the trade.
Aquamarine is beryl (Be₃Al₂Si₆O₁₈) colored by Fe²⁺ for blue and Fe³⁺ for yellow-green secondary tones. Almost all commercial aquamarine is heat-treated at around 400 °C to drive off the yellow component and leave pure blue. Major sources include Brazil (Minas Gerais), Mozambique, Madagascar, Pakistan, and Nigeria.
Origins
Brazil's Minas Gerais (Santa Maria de Itabira, Marambaia) is the historic source of the deepest, purest blue. Mozambique's Pomba mine has supplied excellent material since the 1990s. Madagascar yields large clean crystals, sometimes with notable saturation. Pakistan's Shigar Valley produces strongly saturated stones, often called 'Santa Maria Africana' or 'Shigar blue.'
History
Roman sailors carried aquamarine as a talisman for safe passage — the name comes from Latin aqua marina, sea water. Notable specimens include the Dom Pedro Aquamarine (10,363 ct), the largest cut aquamarine in the world, on display at the Smithsonian.
Lore & symbolism
March's birthstone, symbolizing courage, calm, and the sea. The 19th wedding anniversary stone.
Tools to confirm this stone
Tools that help confirm Aquamarine. 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
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