mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Mohs hardness: 7. Colorless and transparent. Vitreous luster. Hexagonal crystal system (trigonal). Conchoidal fracture. Specific gravity: 2.65.
- Hardness
- 7
Identified More mineral →
Explore Clear Quartz (Rock Crystal) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Mohs hardness: 7. Colorless and transparent. Vitreous luster. Hexagonal crystal system (trigonal). Conchoidal fracture. Specific gravity: 2.65.
Formation & geological history
Forms in a wide variety of geological environments, most commonly in pegmatites, hydrothermal veins, and metamorphic rocks as silica-rich solutions cool and crystallize.
Uses & applications
Used extensively in jewelry, ornamental carvings, electronics (piezoelectric oscillators), optics, and highly sought after by mineral collectors.
Geological facts
Ancient Greeks believed rock crystal was ice frozen so hard it would never melt. It exhibits piezoelectricity, meaning it generates an electric potential under mechanical stress.
Field identification & locations
Identified by its glass-like transparency, ability to scratch glass (hardness 7), and lack of true cleavage. Commonly found worldwide, including Brazil, Arkansas (USA), and Madagascar.
More like this
Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Schist
Schist
Metamorphic
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock