Chalcedony
Quartz var. Chalcedony · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal, microcrystalline habit (crypto-crystalline quartz)
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2
Formation Process
Hydrothermal and low-temperature sedimentary processes involving the deposition of silica from aqueous solutions, often filling cavities in volcanic rocks.
About This Crystal
A small, tumbled, pale bluish-white translucent stone with a smooth polished surface and waxy luster, displaying soft internal cloudiness.
Physical Characteristics
Pale blue-grey body color, white streak, conchoidal fracture, no distinct cleavage, specific gravity of approximately 2.60 to 2.65, brittle tenacity, vitreous to waxy luster.
Optical Properties
Refractive index ranges from 1.530 to 1.540, doubly refractive with aggregate birefringence, typically non-pleochroic due to microcrystalline structure.
Hardness & Durability
Origin Region
Found globally; notable sources include Brazil, India, Madagascar, and the United States. Forms in volcanic cavities, hydrothermal veins, and sedimentary environments.
Hardness & Durability
Mohs hardness of 6.5 to 7, making it durable and suitable for everyday jewelry wear, though care should be taken against hard impacts.
Care & Maintenance
Clean with warm soapy water using a soft brush. Avoid harsh chemical cleaners and prolonged exposure to extreme heat, though standard sunlight is generally safe.
Rarity & Value
Common and widely available, with affordable pricing typically ranging from very low to moderate depending on size, cutting, and specific color varieties.
Special Characteristics
Microfibrous structure composed of quartz and moganite intergrowths; may exhibit subtle translucency and internal banding.
Lore & History
Historically used by ancient civilizations for carved seals, beads, and ornamental objects. In modern metaphysical practices, it is often associated with emotional balance, calm communication, and the throat chakra.