mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale), Color: Colorless/Transparent, Luster: Vitreous (glassy), Crystal system: Trigonal/Hexagonal, Cleavage: None/Conchoidal fracture, Specific gravity: 2.65

Identified June 17, 2026More mineral →

Explore Clear Quartz (Rock Crystal) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 (Mohs scale), Color: Colorless/Transparent, Luster: Vitreous (glassy), Crystal system: Trigonal/Hexagonal, Cleavage: None/Conchoidal fracture, Specific gravity: 2.65

Formation & geological history

Quartz forms through the cooling of silica-rich magma or from hydrothermal solutions. It is found in igneous, metamorphic, and sedimentary environments globally, and can be billions of years old.

Uses & applications

Used in jewelry, precision watches (oscillators), glassmaking, electronics, and as a popular decorative or healing crystal for collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's crust. 'Rock Crystal' specifically refers to the purest, water-clear variety. Large crystals have been found weighing several tons.

Field identification & locations

Identified by its hexagonal crystal habit, hardness (will scratch glass), and lack of cleavage. Common in granite pegmatites and quartz veins worldwide, particularly in Brazil and Arkansas, USA.