Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal, typically forming prismatic crystals terminating in six-sided pyramids
Mineral Group
Silicates, specifically Tectosilicates
Chemical Formula
SiO2
Formation Process
Hydrothermal and magmatic processes, precipitating from silica-rich solutions at low to moderate temperatures with trace iron irradiation
About This Crystal
Small, transparent to translucent crystal fragment exhibiting pale to medium purple color zoning and distinct internal phantom or growth line inclusions
Physical Characteristics
Light purple to violet body color, white streak, conchoidal fracture, lack of cleavage, specific gravity of approximately 2.65, brittle tenacity, and piezoelectric properties
Optical Properties
Uniaxial positive optical character, refractive index of 1.544 to 1.553, weak birefringence, and faint dichroism showing reddish-purple and bluish-purple hues
Hardness & Durability
Origin Region
Found globally with notable sources in Brazil, Uruguay, Madagascar, and Zambia; forms in volcanic cavities, hydrothermal veins, and pegmatites
Hardness & Durability
Mohs hardness of 7, making it durable for daily jewelry wear, though susceptible to thermal shock and scratching by harder minerals like corundum or topaz
Care & Maintenance
Clean safely with warm soapy water and a soft brush; avoid ultrasonic cleaners if fractures are present and protect from prolonged direct sunlight to prevent color fading
Rarity & Value
Common to uncommon depending on clarity and saturation, with value determined by deep purple color saturation, lack of inclusions, and size; heat treatments are occasionally used to convert it to citrine
Special Characteristics
Often exhibits color zoning, phantom inclusions, and natural irradiation-induced color centers that can be thermally unstable
Lore & History
Historically worn by ancient Greeks and Romans to prevent intoxication, associated with royalty, peace, and spiritual growth, commonly linked to the third eye and crown chakras in modern metaphysical lore