mineral

Quartz (Clear/Smoky Geode fragment)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Colorless to greyish-lilac; Luster: Vitreous (glassy); Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Colorless to greyish-lilac
Luster: Vitreous (glassy)

Identified May 23, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale; Color: Colorless to greyish-lilac; Luster: Vitreous (glassy); Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed via hydrothermal activity where silica-rich fluids precipitate in rock cavities (vugs) or gas bubbles in volcanic rock. These specimens can range from thousands to millions of years old based on the host rock formation.

Uses & applications

Used extensively in industry for glassmaking, abrasives, and electronics (due to piezoelectric properties). Highly valued in jewelry as semi-precious stones and popular in metaphysical and crystal collections.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is known as rock crystal, while impurities create variants like amethyst or citrine.

Field identification & locations

Identify by its inability to be scratched by steel, its glassy luster, and the presence of hexagonal pyramidal crystal terminations. Found globally in all types of geological environments.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral