Amethyst
Variety of quartz
Common · SiO₂
A variety of quartz coloured by iron impurities and natural irradiation. The commercially important deposits line the gas cavities of volcanic basalts, in geodes large enough to stand in. Heating turns some amethyst yellow, into citrine; too much heat bleaches it.
Identity
- Formula
- SiO₂
- Chemical class
- Silicate
- Mineral group
- Agate, Bloodstone, Carnelian, Chalcedony, Citrine, Jasper, Moss Agate, Onyx, Quartz, Rose Quartz, Smoky Quartz, Tiger's Eye
- Also known as
- Purple quartz, Violet quartz
- Used in alchemy
- Amethyst Powder
Crystallography
- Crystal system
- Trigonal
- Habits
- Prismatic, Drusy
- Fracture
- Conchoidal
Physical properties
- Mohs hardness
- 7
- Density
- 2.65 g/cm³
- Luster
- Vitreous
- Colors
- purple, violet, pale purple, deep purple
- Streak
- white
- Transparency
- Transparent, Translucent
Geology
- Origins
- Hydrothermal, Igneous
- Host rocks
- Granite, Volcanic rock
- Associated minerals
- Calcite, Quartz, Goethite
- Geography
- Brazil, Uruguay, Zambia, Russia, South Korea
Classification
- Rarity
- Common
- Gem quality
- Yes
Arcane properties
- Affinity
- Arcane, Mind
- Effects
- Mind, Warding
- Planar origin
- Material Plane
Sources
- Amethyst. Mindat.org (Hudson Institute of Mineralogy).
- Quartz. Mindat.org (Hudson Institute of Mineralogy).
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Quartz. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Amethyst. Gemdat.org (Hudson Institute of Mineralogy).
- February Birthstone. Gemological Institute of America.
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