Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal, typically forming prismatic crystals ending in a six-sided pyramid
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2
Formation Process
Hydrothermal veins and volcanic cavities (geodes) at low to moderate temperatures
About This Crystal
A small, tumbled, deep purple polished gemstone displaying translucent to transparent clarity with vitreous luster and subtle color zoning.
Physical Characteristics
Purple body color, white streak, conchoidal fracture, lack of cleavage, specific gravity of approximately 2.65, brittle tenacity, and generally non-fluorescent though sometimes weak blue or green under shortwave UV
Optical Properties
Uniaxial positive optical character, refractive index of 1.544 to 1.553, low birefringence of 0.009, and faint dichroism showing reddish-purple and bluish-purple
Hardness & Durability
Origin Region
Brazil, Uruguay, Madagascar, Zambia, and the United States
Hardness & Durability
Mohs hardness of 7, fair toughness due to lack of cleavage, stable under normal wear conditions but sensitive to extreme heat and prolonged direct sunlight
Care & Maintenance
Clean with warm soapy water using a soft brush, avoid harsh chemicals, ultrasonic cleaners, and steam cleaning, and store away from direct sunlight and harder gemstones
Rarity & Value
Common to moderately rare depending on saturation, priced affordably as tumbled stones, with heat treatment and irradiation sometimes used to alter color
Special Characteristics
Piezoelectric and pyroelectric properties, often exhibits color zoning and phantom crystal growth structures
Lore & History
Historically used by ancient Greeks and Romans as an amulet to prevent intoxication and maintain a clear mind, commonly associated today with the Third Eye and Crown chakras for spiritual growth and calm