Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal, with a massive or microcrystalline habit as tumbled stone
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2
Formation Process
Hydrothermal and magmatic processes, typically forming within cavities in volcanic rocks (geodes) at low to moderate temperatures
About This Crystal
A polished, tumbled specimen exhibiting distinct zones of deep purple and milky white chevron or banded patterns, displaying a vitreous to waxy luster and semi-translucent to opaque clarity
Physical Characteristics
Purple to violet color with white banding (streak is white), conchoidal fracture, no true cleavage, specific gravity of approximately 2.65, brittle tenacity
Optical Properties
Uniaxial positive optical character with a refractive index of 1.544 to 1.553, and a birefringence of 0.009
Hardness & Durability
Origin Region
Brazil, Uruguay, Madagascar, Zambia, and parts of the United States
Hardness & Durability
Mohs hardness of 7, making it durable for general jewelry use with fair toughness and no cleavage planes
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid harsh chemicals, ultrasonic cleaners, and prolonged exposure to direct sunlight which can cause the purple color to fade
Rarity & Value
Common, widely available globally, with value determined by color saturation, clarity, and size, frequently subjected to heat treatment to produce yellow citrine
Special Characteristics
Exhibits distinct chevron color-zoning banding composed of alternating layers of purple amethyst and white quartz
Lore & History
Historically worn in ancient times to prevent drunkenness and ensure a clear head; associated in modern crystal healing with the third eye and crown chakras, believed to promote calm, spiritual growth, and emotional balance