Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal, crystal habit typically forms as prismatic crystals terminating in pyramids, though as a tumbled gemstone it presents as irregular, smoothed fragment shapes known as chip beads
Mineral Group
Silicates, specifically Tectosilicates
Chemical Formula
SiO2
Formation Process
Hydrothermal and magmatic processes, forming as silica-rich solutions precipitate in cavities of volcanic rocks at low to moderate temperatures, where trace iron is irradiated by natural gamma radiation
About This Crystal
A stretch bracelet composed of tumbled, polished irregular chips of amethyst showing a spectrum of purple colors ranging from pale lilac to deep violet, with semi-translucent to transparent clarity and a vitreous to waxy luster
Physical Characteristics
Purple body color, white streak, no cleavage, conchoidal fracture, specific gravity around 2.65, brittle tenacity, and generally inert under UV light though some specimens show weak green or blue fluorescence
Optical Properties
Uniaxial positive optical character, refractive index of 1.544 to 1.553, weak birefringence of 0.009, and faint dichroism showing reddish-purple and bluish-purple shades from different angles
Hardness & Durability
Origin Region
Global distribution with major commercial sources in Brazil, Uruguay, Madagascar, Zambia, and the United States; forms within hydrothermal veins, volcanic gas cavities, and pegmatites
Hardness & Durability
Mohs hardness of 7, making it durable enough for everyday jewelry wear like bracelets, though susceptible to scratching softer materials and vulnerable to sharp impacts due to lack of cleavage
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; value depends on color saturation, clarity, and size, with deep purple Siberian or Uruguayan grades commanding higher prices while tumbled chip beads are very affordable and widely accessible
Special Characteristics
Color zoning is often visible in larger crystals, along with subtle piezoelectric and pyroelectric properties inherent to the quartz family
Lore & History
Historically worn by ancient Greeks and Romans to prevent intoxication, symbolizing sobriety and clear-headedness; in modern crystal healing, it is associated with the third eye and crown chakras, promoting calm, spiritual growth, and emotional balance