Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal; Hexagonal prisms terminated by two sets of rhombohedrons. This specimen is in a 'tumble-polished' massive habit.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide) with trace amounts of Fe3+ (Iron) and natural irradiation
Formation Process
Hydrothermal; forms from silica-rich solutions in cavities (amygdules) within volcanic rocks or in hydrothermal veins at low to moderate temperatures.
About This Crystal
Deep purple to violet body color with distinct white quartz banding (chevron pattern). This specimen is a rounded, tumbled stone with a vitreous (glassy) luster, transitioning from translucent to opaque in dark zones.
Physical Characteristics
Color: Violet/Purple. Streak: White. Cleavage: None. Fracture: Conchoidal. Specific Gravity: 2.65. Tenacity: Brittle. Typically non-fluorescent, though some show weak weak bluish-white under UV.
Optical Properties
Refractive Index: 1.544-1.553. Birefringence: 0.009. Pleochroism: Weak to moderate, purple and reddish-purple. Doubly refractive (uniaxial positive).
Hardness & Durability
Origin Region
Major sources include Brazil (Rio Grande do Sul), Uruguay, Madagascar, and Zambia. Commonly found in volcanic geodes and pegmatites.
Hardness & Durability
Mohs Hardness: 7. Toughness: Good (no cleavage). Very durable for jewelry, though softer than topaz or sapphire.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid ultrasonic cleaners if inclusions are present. Keep away from prolonged direct sunlight as it may cause the purple color to fade over time.
Rarity & Value
Common. Value is determined by color depth ('Siberian' deep purple is most prized), clarity, and size. Frequently heat-treated to produce citrine or prasiolite.
Special Characteristics
Color zoning is common. This specific specimen exhibits 'Chevron' patterns, which are V-shaped layers of white milky quartz and purple amethyst.
Lore & History
Ancient Greeks believed it prevented intoxication (amethystos means 'not drunk'). It has been used in royal jewelry for centuries. In modern metaphysical practices, it is associated with the Third Eye and Crown Chakras, believed to promote calm, clarity, and spiritual protection.