Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal, with a typical habit of hexagonal prisms terminating in pyramids, though when cut as a gemstone it is faceted into standard shapes like the oval shown.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2
Formation Process
Hydrothermal and magmatic processes, precipitating from silica-rich solutions at low to moderate temperatures within cavities in volcanic rocks.
About This Crystal
The specimen features an oval-cut, transparent to translucent purple gemstone set in an ornate silver ring. The stone displays a deep violet to purple coloration with internal faceting and minor natural color zoning typical of quartz varieties.
Physical Characteristics
Body color ranges from pale lilac to deep purple; streak is white; no cleavage; fracture is conchoidal; specific gravity is approximately 2.65; tenacity is brittle; exhibits piezoelectric properties.
Optical Properties
Singly or doubly refractive (uniaxial positive); refractive index of 1.544 to 1.553; weak birefringence of 0.009; weak pleochroism showing reddish-purple and bluish-purple hues.
Hardness & Durability
Origin Region
Notable sources include Brazil, Uruguay, Madagascar, Zambia, and the United States. They typically form in volcanic cavities, basaltic gas vesicles, and hydrothermal veins.
Hardness & Durability
Mohs hardness of 7, making it durable and suitable for everyday jewelry wear such as rings and pendants, with fair toughness and no cleavage planes.
Care & Maintenance
Clean with warm soapy water using a soft brush. Avoid ultrasonic cleaners and steam if fractures are present. Store away from direct sunlight to prevent color fading over prolonged periods.
Rarity & Value
Common to moderately rare depending on saturation and clarity; high-grade deep purple stones from Siberia or Uruguay command higher prices, while treatments like heat-treating lower-grade stones to yellow (citrine) are common.
Special Characteristics
Natural color zoning, potential for phantom inclusions or fluid inclusions, and strong piezoelectric properties.
Lore & History
Historically worn by ancient Greeks and Romans to prevent intoxication (derived from the Greek 'amethystos', meaning 'not drunken'). In modern crystal healing, it is traditionally associated with the third eye and crown chakras, promoting peace, clarity, and spiritual growth, though these are traditional beliefs rather than scientific claims.