Quartz (Clear Quartz / Rock Crystal)
Image: Ray Swi-hymn from Sijhih-Taipei, Taiwan (CC BY-SA 2.0)
Mineral NameQuartz (Clear Quartz / Rock Crystal)
Chemical FormulaSiO₂
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorscolorless
Transparencytransparent
Type LocalityUbiquitous; significant sources include Brazil, Arkansas (USA), Alps, Madagascar.
Mineral GroupSilicates
Usesjewelry, industrial, collector specimens
Associated Mineralsfeldspar, mica, tourmaline
Raritycommon
Description
A common, hard, colorless, and transparent mineral, typically forming hexagonal prisms with pyramidal terminations, exhibiting a glassy luster.
Geological Context
Quartz is a primary constituent of many igneous, metamorphic, and sedimentary rocks. It crystallizes from magma and hydrothermal solutions, and is highly resistant to weathering, accumulating in sediments.
