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Green Spinel
| Hardness | 8 |
| Specific gravity | 3.60 |
| Refractive index | 1.718 |
| Crystal system | 等軸晶系 |
Bright grass green, bottle green, and bluish green. Iron and chromium are the primary chromophores.
- Octahedral nclusions — diagnostic for the spinel group
- Zircon crystals surrounded by tension halos
- Clusters of small crystals along healed fractures
- Generally cleaner content than corundum
- Singly refractive (cubic system) — no
- No
- Refractive index 1.712–1.717
- Specific gravity 3.58–3.62
- 01egative crystals are diagnostic
- 02Singly refractive — no at 10× separates green spinel from green sapphire (doubly refractive, with )
- 03Mohs 8 — softer than corundum (Mohs 9) but harder than most green substitutes
- 04Cleaner content than equivalent green sapphire is itself a clue
- Mohs 8 — suitable for daily wear
- Ultrasonic and steam cleaning are normally safe
- Stable to light and ordinary chemicals
A few thousand yen per carat for ordinary material up to several tens of thousands of yen per carat for top-color Burmese or Vietnamese stones above 1 ct.
Note: Burmese material from Mogok commands the highest prices; Sri Lankan, Tajik, Vietnamese, and Tanzanian material is more accessible. No treatments are routinely applied to spinel, which is one of the few major gem species that remains overwhelmingly untreated.
Green spinel is magnesium-aluminum oxide (MgAl₂O₄) colored mainly by iron, sometimes with a chromium component that pushes the tone toward emerald-green. The cubic means there is no and no — clean stones look almost too clear to be natural. Major production is limited and intermittent: Mogok in Myanmar has been the historic source, with periodic finds from Sri Lanka, Tajikistan, Vietnam, and Tanzania. The 2016 of spinel as an additional August birthstone by AGTA gave the entire group, including the green variety, a major commercial boost.
Origins
Mogok in Myanmar is the historic and benchmark source, producing material that ranges from deep bottle-green to bluish green. Sri Lanka (Ratnapura), Tajikistan (Kuh-i-Lal — the same pegmatite that produced the famous Black Prince's Ruby, which is actually red spinel), Vietnam (Luc Yen), and Tanzania (Mahenge) supply smaller quantities. Stones above 1 ct in clean green color are decidedly rare from any source; the trade routinely substitutes treated tourmaline or chrysoprase for green spinel in commercial mountings.
History
Green spinel was a minor category in the historic gem trade — almost all the legendary 'spinels' of Mughal and Persian regalia were red, and green spinel did not enter the international colored-stone market in any quantity until the late 20th-century revival of the Mogok mines after Burmese liberalization in the 1990s. The 2016 AGTA decision to add spinel as a secondary August birthstone alongside peridot drove sharp growth in spinel pricing across all colors, including green.
Lore & symbolism
August birthstone, added by AGTA in 2016 to share the month with peridot. The 'forest spirit' stone of contemporary lapidary writing — associated with harmony, growth, and emotional balance.
Tools to confirm this stone
Tools that help confirm Green Spinel. 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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