Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal, typically forming as prismatic crystals terminated by pyramids or within geodes and massive habits; this specimen is a tumbled/polished stone.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2
Formation Process
Hydrothermal and magmatic processes, precipitating from silica-rich solutions at low to moderate temperatures, with color imparted by natural irradiation of trace iron impurities.
About This Crystal
A tumbled, polished smooth specimen of transparent to translucent purple quartz, displaying light to medium violet color zoning, vitreous luster on polished surfaces, and internal fractures or cloud-like inclusions typical of natural quartz.
Physical Characteristics
Purple body color with a white streak; conchoidal fracture with no true cleavage; specific gravity of approximately 2.65; brittle tenacity; exhibits piezoelectric properties.
Optical Properties
Uniaxial positive optical character with a refractive index of 1.544-1.553, low birefringence of 0.009, and faint dichroism showing reddish-purple and bluish-purple hues.
Hardness & Durability
Origin Region
Brazil, Uruguay, Madagascar, Zambia; typically forms in volcanic rock cavities (vesicles) and hydrothermal veins.
Hardness & Durability
Mohs hardness of 7; good durability for daily wear in jewelry, though care must be taken with hard impacts due to brittleness.
Care & Maintenance
Clean with warm soapy water using a soft brush; avoid harsh chemicals, steam cleaners, and prolonged exposure to direct sunlight which can cause fading.
Rarity & Value
Common; value depends on color saturation, clarity, and size, ranging from inexpensive tumbled stones to high-value collector gemstones; heat treatments to yellow (citrine) or green are sometimes performed on lower-grade material.
Special Characteristics
Natural color zoning and internal phantom or inclusion features are visible; exhibits piezoelectricity and occasional weak fluorescence under shortwave UV light.
Lore & History
Historically worn in ancient times to prevent drunkenness and ensure a clear mind; culturally associated with royalty, peace, and spiritual growth, commonly linked to the third eye and crown chakras in modern metaphysical practices.