identified this stone yet
Amethyst
| Hardness | 7 |
| Specific gravity | 2.65 |
| Refractive index | 1.544-1.553 |
| Crystal system | 六方晶系（三方晶系） |
Pale lilac through medium purple to deep reddish purple. The trade term 'Siberian' refers to the top color — deep purple with red and blue flashes — regardless of origin.
- Tiger-stripe color zoning
- nclusions
- nclusions
- Goethite needles in rare specimens
- Doubly refractive, uniaxial positive
- Weak dichroism: purple and reddish purple
- 01Tiger-stripe color zoning visible under immersion suggests natural origin
- 02Synthetic amethyst shows no natural zoning and is essentially clean
- 03nclusions or zoning are suspicious — most natural amethyst shows at least some color banding
- Durable for daily wear
- Avoid prolonged direct sunlight — can fade over decades in some material
- Safe to ultrasonic and warm soapy water
From $5/ct for pale commercial material up to $80/ct for fine deep 'Siberian' color in larger sizes.
Note: Heat treatment turns amethyst into citrine, prasiolite (green quartz), or ametrine — most commercial citrine on the market is heat-treated amethyst. Untreated amethyst is the norm. Synthetic amethyst is common but hard to detect without specialized equipment.
Amethyst is quartz (SiO₂) colored by Fe³⁺ centers activated by natural irradiation in the host rock. Major sources include Brazil (Rio Grande do Sul), Uruguay (Artigas), Zambia (Kariba), Bolivia, and Madagascar. Mohs 7 makes it suitable for any jewelry use.
Origins
Brazil produces the largest volume, often in vast geodes. Uruguayan amethyst from Artigas tends toward deeper, more saturated purple in smaller crystals. Zambia's Kariba mine produces particularly fine, slightly bluish purple stones — often the source of 'African amethyst' in the modern market.
History
The Greeks named it amethystos — 'not drunken' — believing it prevented intoxication, and carved drinking cups from it. Roman, Byzantine, and Egyptian jewelry includes amethyst extensively. The 18th-century Brazilian discoveries made amethyst affordable enough to leave the cardinal's-stone category and reach a wider public.
Lore & symbolism
February's birthstone, symbolizing clarity, sobriety, and spiritual focus. The 6th and 33rd wedding anniversary stone.
Tools to confirm this stone
Tools that help confirm Amethyst. Tap any item to jump to the matching section on the gem tools page.
- Last reviewed
- April 28, 2026
- Bibliography
- Gem Encyclopedia / GIA (Gemological Institute of America)
- Gem Identification Standards / Central Gem Laboratory (CGL), Tokyo
- Mineral & Gem Database / Mindat.org / Gemdat.org
- Introduction to Gemology / Gemmological Association of All Japan (GAAJ)
The gemological data on this page (refractive index, specific gravity, hardness, crystal system, etc.) is cross-checked against the authoritative primary sources listed above. Values may be revised as gemological research advances.