Rock Crystal
Quartz var. Rock Crystal · Semi-Precious Gemstone and Mineral Specimen
Crystal System
Trigonal system, typically forming prismatic crystals terminated by rhombohedra, often exhibiting doubly terminated habits in certain environments like Herkimer diamonds.
Mineral Group
Silicate mineral group, specifically within the tectosilicate subgroup.
Chemical Formula
SiO2
Formation Process
Hydrothermal and pegmatitic processes where silica-rich fluids cool and crystallize under specific temperature and pressure conditions within cavities or fractures.
About This Crystal
A clear, transparent doubly terminated quartz crystal showing glassy vitreous luster with internal fractures and characteristic growth phantoms or fluid inclusions visible inside the matrix.
Physical Characteristics
Colorless body color with a white streak, conchoidal fracture, absence of true cleavage, specific gravity of approximately 2.65, brittle tenacity, and displays piezoelectric properties.
Optical Properties
Uniaxial positive optic sign with a refractive index ranging from 1.544 to 1.553, birefringence of 0.009, and exhibits no pleochroism due to being colorless.
Hardness & Durability
Origin Region
Found worldwide, with major notable sources including Brazil, Madagascar, the United States (such as Herkimer County, New York), the Alpine regions of Europe, and the Himalayas.
Hardness & Durability
Mohs hardness of 7, making it durable and suitable for everyday jewelry use, with good resistance to scratching but brittle upon heavy impact.
Care & Maintenance
Can be safely cleaned with warm soapy water and a soft brush; avoid harsh chemicals and extreme thermal shock. Store separately from softer stones to prevent scratching.
Rarity & Value
Commonly found globally, with value determined by clarity, perfection of termination, size, and presence of unique inclusions. Generally affordable unless sourced from prestigious localities.
Special Characteristics
Displays double termination (terminated crystals on both ends) and internal phantom growth lines or minor fluid inclusions captured during formation.
Lore & History
Historically used across ancient civilizations for divination, bowls, and jewelry. In modern metaphysical practices, it is known as the master healer stone, traditionally associated with the Crown Chakra and amplification of energy.