gemstone
Clear Quartz (Rock Crystal)
Crystalline Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Colorless/Transparent
- Luster
- Vitreous (glassy)
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 on Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed in igneous, metamorphic, and sedimentary environments through hydrothermal activity or the cooling of silica-rich magma/fluids. Found in veins and geodes globally.
Uses & applications
Used in jewelry as a gemstone, in glassmaking, as a frequency control in electronics (piezoelectric properties), and as a popular collector specimen.
Geological facts
Ancient Greeks called quartz 'krystallos', meaning 'ice', believing it was water permanently frozen by the gods. It is the second most abundant mineral in the Earth's continental crust.
Field identification & locations
Identify by its clarity, ability to scratch glass (hardness 7), and lack of cleavage. This specific specimen appears to be a faceted or step-cut gemstone, possibly set in a bezel-style mounting.
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
Amber
Succinrite (Organic Gemstone)
mineraloid