Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal, with a typical macrocrystalline habit forming prismatic crystals terminated by pyramids, though this specimen is a tumbled and polished pebble.
Mineral Group
Silicates, specifically Tectosilicates
Chemical Formula
SiO2
Formation Process
Hydrothermal and magmatic processes where silica-rich solutions precipitate quartz in cavities at low to moderate temperatures, with coloration induced by natural irradiation of trace iron impurities.
About This Crystal
A polished, tumbled pebble of deep purple quartz displaying characteristic color zoning and translucent to transparent clarity with a vitreous to waxy luster.
Physical Characteristics
Color ranges from pale lilac to deep violet; streak is white; cleavage is absent (exhibits conchoidal fracture); specific gravity is approximately 2.65; brittle tenacity; exhibits piezoelectric and pyroelectric properties.
Optical Properties
Uniaxial positive, doubly refractive with a weak birefringence of 0.009, and faint pleochroism showing reddish-purple and bluish-purple shades.
Hardness & Durability
Origin Region
Found globally with notable sources in Brazil, Uruguay, Madagascar, Zambia, and the United States. Forms primarily in hydrothermal veins and gas cavities (vugs/geodes) within volcanic rocks.
Hardness & Durability
Mohs hardness of 7, good durability and toughness, making it highly suitable for everyday jewelry wear despite lacking cleavage.
Care & Maintenance
Easy to maintain; can be cleaned with warm soapy water and a soft brush. Avoid prolonged exposure to direct sunlight to prevent color fading, and keep away from harsh hydrofluoric acids.
Rarity & Value
Common to moderately rare depending on saturation; deep Siberian or Uruguayan grades command higher values, while commercial tumbled stones are widely accessible and affordable.
Special Characteristics
Often exhibits distinct color zoning, phantom growth lines, and natural or artificial irradiation responses, along with piezoelectric properties.
Lore & History
Historically worn by ancient Greeks and Romans to prevent drunkenness and ensure a clear mind. In modern crystal healing, it is traditionally associated with the third eye and crown chakras, symbolizing spiritual growth, calmness, and protection.