mineral

Quartz (Common or Milky Quartz)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: white, off-white, or translucent cream; Luster: vitreous to greasy; Crystal Structure: Trigonal (Hexagonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: white, off-white, or translucent cream
Luster: vitreous to greasy

Identified July 18, 2026More mineral →

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Physical properties

Formation & geological history

Quartz forms in a wide variety of environments, most commonly by crystallizing from cooling magma or precipitating from hydrothermal veins. It is found in all three major rock types and across all geological ages.

Uses & applications

Used extensively in glassmaking, abrasives, jewelry, electronics (due to piezoelectric properties), and as a primary component in concrete and construction aggregates.

Geological facts

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

Field identification & locations

Identify in the field by its hardness (it will scratch glass), its lack of cleavage (it breaks in irregular or curved shell-like shapes), and its resistance to acid. Common in mountains and as gravel in riverbeds worldwide.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Sandstone with Mineral Veining or Crust

Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)

sedimentary

Schist

Metamorphic

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

mineral

Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

Mineral

Nephrite Jade

Nephrite

Mineral/Rock