mineral

Quartz (specifically Milky Quartz or Quartzite)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale (scratches glass); Color: White, translucent to milky opaque; Luster: Vitreous (glassy) to greasy; Crystal Structure: Hexagonal (Trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale (scratches glass)
Color: White, translucent to milky opaque
Luster: Vitreous (glassy) to greasy

Identified March 21, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of silica-rich magma or through hydrothermal activity in veins. It can also form the bulk of metamorphic quartzite. Native to almost all geological ages due to its stability.

Uses & applications

Used in construction as a component of concrete or road base. In industry, it is a source of silicon for electronics and glass making. Low-grade specimens like this are used for landscaping or aggregate.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is piezoelectric, meaning it generates an electric charge in response to applied mechanical stress, a property used in watches and radios.

Field identification & locations

Identify by its hardness (it will easily scratch a steel knife blade or glass) and its lack of cleavage (it breaks in irregular, curvy surfaces). Commonly found in gravel pits, riverbeds, and mountain outcrops. Collectors look for well-defined crystal points which this specimen lacks.

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