Amethyst
Quartz var. Amethyst · Semi-Precious Gemstone
Crystal System
Trigonal system, typically forming prismatic crystals terminated by rhombohedrons
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide with trace iron impurities)
Formation Process
Hydrothermal and magmatic processes, forming in cavities of volcanic rocks at low to moderate temperatures with irradiation of trace iron impurities.
About This Crystal
Large, cushion-cut deep purple gemstone set in a ring flanked by smaller accent stones, displaying high transparency and a checkerboard faceting pattern.
Physical Characteristics
Deep purple body color, white streak, distinct conchoidal fracture, completely lacking cleavage, specific gravity of approximately 2.65, brittle tenacity.
Optical Properties
Uniaxial positive optical character with a refractive index of 1.544 to 1.553, low birefringence of 0.009, and faint weak dichroism.
Hardness & Durability
Origin Region
Notable sources include Brazil, Uruguay, Madagascar, and Zambia. Forms in igneous and metamorphic rocks, commonly within gas cavities in basaltic lavas (geodes).
Hardness & Durability
Mohs hardness of 7, offering good durability and wearability suitable for everyday rings, though vulnerable to severe impacts due to brittleness.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid ultrasonic cleaners if fractures are present, and protect from prolonged direct sunlight to prevent color fading.
Rarity & Value
Common to moderately rare depending on saturation; highly saturated deep purple stones with clean clarity command higher value. Heat treatments are sometimes used to convert lower quality material to citrine or green quartz.
Special Characteristics
Displays color zoning typical of natural quartz crystals, along with high clarity and checkerboard table cuts that enhance light play.
Lore & History
Historically associated with royalty, sobriety, and spiritual protection in ancient Greek, Roman, and Egyptian cultures. In modern crystal healing, it is linked to the third eye and crown chakras for promoting peace and clarity.