gemstone
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Hardness: 7 Mohs; Color: Colorless/Transparent; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct; Specific Gravity: 2.65
- Hardness
- 7 Mohs
- Color
- Colorless/Transparent
- Luster
- Vitreous
Identified More gemstone →
Explore Clear Quartz (Rock Crystal) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 Mohs; Color: Colorless/Transparent; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct; Specific Gravity: 2.65
Formation & geological history
Forms in a wide range of geological environments, most notably in hydrothermal veins and pegmatites, where mineral-rich hot water cools and allows crystals to grow.
Uses & applications
Used in jewelry, precision instruments (quartz oscillators), glass making, and as a popular collector's specimen.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is traditionally called rock crystal or clear quartz.
Field identification & locations
Identify by its hardness (scratches glass), lack of air bubbles (unlike glass), and hexagonal crystal habit. Found globally in mountainous regions.
More like this
Other gemstone specimens
Ammolite
Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)
mineral
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Amber
Succinite (Organic Gemstone)
mineral
Citrine
Silicon Dioxide (SiO2) with iron impurities
mineral
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)
mineral
Emerald
Beryl (Be₃Al₂Si₆Oထ₈) with Chromium/Vanadium impurities
gemstone