Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal, with a microcrystalline to macrocrystalline quartz habit; typically tumbled into a smooth, rounded pebble shape in this specimen.
Mineral Group
Silicates (Subgroup: Tectosilicates)
Chemical Formula
SiO2
Formation Process
Hydrothermal and magmatic processes, typically forming within cavities (vugs and geodes) in basaltic volcanic rocks at low to moderate temperatures from silica-rich aqueous solutions containing trace iron.
About This Crystal
A tumbled, polished smooth specimen displaying a pale to medium purple and violet color with cloudy white quartz inclusions and mottled color zoning. It is translucent to opaque with a vitreous to waxy luster typical of tumbled quartz.
Physical Characteristics
Color ranges from light lilac to deep purple with white patches; white streak; no true cleavage; conchoidal fracture; specific gravity of approximately 2.65; brittle tenacity; exhibits piezoelectricity.
Optical Properties
Uniaxial positive with a refractive index of 1.544 to 1.553, low birefringence of 0.009, and faint dichroism in shades of purple and reddish-purple.
Hardness & Durability
Origin Region
Global distribution with notable deposits in Brazil, Uruguay, Madagascar, Zambia, and the United States (Thunder Bay, Arizona).
Hardness & Durability
Mohs hardness of 7, making it durable and suitable for everyday jewelry wear like rings and pendants, with no distinct cleavage planes to worry about.
Care & Maintenance
Safe to clean with warm soapy water and a soft brush; avoid ultrasonic or steam cleaners if heat-treated or heavily included. Store away from direct sunlight for prolonged periods to prevent color fading.
Rarity & Value
Common; widely available worldwide. Value depends on color saturation, clarity, and size. Most commercial tumbled stones are inexpensive, though intensely saturated deep purple stones with high clarity command higher prices.
Special Characteristics
Often exhibits chevron banding or zoning when combined with white quartz (Chevron Amethyst), and can be piezoelectric and pyroelectric.
Lore & History
Historically worn by ancient Greeks and Romans to prevent intoxication (derived from the Greek 'amethystos', meaning 'not drunken'). Highly regarded as a stone of spiritual growth, protection, and calm, traditionally associated with the third eye and crown chakras in modern crystal healing.