Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal, commonly occurs as prismatic crystals terminated by rhombohedra or as massive geodes and tumbled stones
Mineral Group
Silicates, specifically Tectosilicates
Chemical Formula
SiO2 with trace amounts of iron (Fe3+)
Formation Process
Hydrothermal and magmatic processes, typically forming within gas cavities in volcanic rocks (basaltic geodes) at low to moderate temperatures
About This Crystal
A polished, tumbled stone displaying a translucent to semi-transparent violet to light purple body color with characteristic uneven color zoning and minor internal fractures or inclusions typical of natural quartz
Physical Characteristics
Color ranges from pale lilac to deep purple; white streak; no true cleavage, exhibits conchoidal fracture; specific gravity of approximately 2.65; brittle tenacity; highly resistant to chemical attack
Optical Properties
Uniaxial positive optical character; refractive index of 1.544-1.553; birefringence of 0.009; typically weak pleochroism showing reddish-violet and bluish-violet
Hardness & Durability
Origin Region
Found globally with notable sources in Brazil, Uruguay, Madagascar, Zambia, and the United States
Hardness & Durability
Mohs hardness of 7; good durability for everyday jewelry wear although care should be taken against heavy impacts due to brittleness
Care & Maintenance
Safe to clean with warm soapy water; avoid prolonged exposure to direct sunlight which can cause the purple coloration to fade; ultrasonic cleaners are generally safe but steam cleaning should be avoided
Rarity & Value
Common to moderately rare depending on saturation and clarity; value increases significantly with deep purple saturation and high transparency; generally affordable for tumbled specimens
Special Characteristics
Exhibits natural color zoning, piezoelectric and pyroelectric properties
Lore & History
Historically used by ancient Greeks and Romans as an amulet to prevent intoxication; traditionally associated with the third eye and crown chakras, representing spiritual growth, calm, and protection