Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal, massive to crystalline habit with typical prismatic terminations when well-formed
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2
Formation Process
Hydrothermal and magmatic processes, forming within gas cavities in volcanic rocks (geodes) at low to moderate temperatures
About This Crystal
Raw, rough purple quartz crystal fragment displaying translucent to transparent areas with a vitreous to greasy luster and irregular fracture surfaces
Physical Characteristics
Purple body color ranging from pale lilac to deep violet, white streak, conchoidal fracture, distinct lack of cleavage, specific gravity of approximately 2.65, brittle tenacity
Optical Properties
Uniaxial positive optical character, doubly refractive with weak birefringence of 0.009, faint pleochroism showing reddish-purple and bluish-purple
Hardness & Durability
Origin Region
Brazil, Uruguay, Madagascar, Zambia, and the USA; typically found in volcanic cavities or hydrothermal veins
Hardness & Durability
Mohs hardness of 7, good wearability for jewelry but brittle and sensitive to extreme thermal shock
Care & Maintenance
Clean with warm soapy water using a soft brush, avoid ultrasonic cleaners and harsh chemicals, protect from prolonged direct sunlight to prevent color fading
Rarity & Value
Common, widely available, value increases with deep color saturation, transparency, and size
Special Characteristics
May exhibit color zoning, phantom growth lines, and piezoelectric properties under mechanical stress
Lore & History
Historically used as an amulet to prevent intoxication and promote clarity of mind; associated with the Third Eye and Crown chakras in modern crystal healing