mineral

Quartz (Milky/Chalcedony variety)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: Translucent white to milky grey, Luster: Vitreous to waxy, Crystal structure: Hexagonal (trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified April 16, 2026More mineral →

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: Translucent white to milky grey, Luster: Vitreous to waxy, Crystal structure: Hexagonal (trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & geological history

Formed from silica-rich hydrothermal fluids cooling in cavities or veins within igneous, metamorphic, or sedimentary rocks. It is found in geological settings ranging from Precambrian eras to modern hydrothermal deposits.

Uses & applications

Industrial use as a source of silicon and glass, microelectronics, watchmaking (piezoelectric properties), and as decorative gravel or tumbled stones for hobbyists.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is highly resistant to chemical and physical weathering, which is why it often survives as sand on beaches and riverbeds.

Field identification & locations

Identify in the field by its hardness (will scratch glass and steel), lack of cleavage, and conchoidal (glass-like) fracture. Found globally in almost all geological environments, especially in gravel pits and mountain veins.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

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