Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal, with a microcrystalline to macrocrystalline quartz habit; typically forms as hexagonal prisms terminating in pyramids, though as a tumbled stone it lacks native crystal faces.
Mineral Group
Silicates (Subgroup: Tectosilicates)
Chemical Formula
SiO2
Formation Process
Hydrothermal and magmatic processes, typically forming in volcanic gas cavities (geodes) at low to moderate temperatures where trace iron is irradiated by natural gamma rays.
About This Crystal
A polished, tumbled smooth stone displaying a translucent light to medium purple (violet) body color with characteristic internal fracture lines, cloudiness, and minor whitish inclusions. The luster is vitreous to greasy due to tumbling and polishing, with a rounded shape fitting comfortably in the palm of the hand.
Physical Characteristics
Color ranges from pale lilac to deep purple; streak is white; no true cleavage, exhibits distinct conchoidal fracture; specific gravity is approximately 2.65; brittle tenacity; displays piezoelectric and pyroelectric properties; generally inert under UV light though some specimens show weak greenish or yellowish fluorescence.
Optical Properties
Singly and doubly refractive (uniaxial positive); refractive index of 1.544-1.553; birefringence of 0.009; weak pleochroism showing reddish-violet and bluish-violet shades from different angles.
Hardness & Durability
Origin Region
Notable sources include Brazil, Uruguay, Madagascar, Zambia, and the United States. Forms commonly in volcanic cavities, hydrothermal veins, and pegmatites.
Hardness & Durability
Mohs hardness of 7, making it durable enough for everyday jewelry use though susceptible to scratching softer glass or being scratched by harder minerals like topaz and corundum. Good toughness with no cleavage planes.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid harsh ultrasonic cleaners, steam cleaners, and prolonged direct exposure to intense sunlight which can cause the purple color to fade over time. Store separately from harder gemstones to prevent scratching.
Rarity & Value
Common to moderately rare depending on saturation and clarity; high-grade deep purple stones from Siberia or Uruguay command higher prices, while tumbled common-grade stones are inexpensive and widely accessible.
Special Characteristics
Often exhibits color zoning (angular zones of darker and lighter purple), natural ghost phantoms, or minor fluid inclusions. Possesses piezoelectric properties, generating an electric charge under mechanical stress.
Lore & History
Historically revered by ancient Greeks and Romans who believed it prevented intoxication (derived from the Greek word 'amethystos', meaning 'not drunken'). Associated with royalty, spiritual clarity, and peace. In modern crystal healing, it is traditionally linked to the third eye and crown chakras to promote intuition and calm.