mineral

Milky Quartz (with Iron Staining)

Silicon Dioxide (SiO2)

Mohs hardness of 7, milky white to translucent color with yellowish-brown iron oxide rust staining, vitreous to greasy luster, trigonal/hexagonal crystal system, indistinct/no cleavage, conchoidal fracture, specific gravity around 2.65.

Identified July 26, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydro-thermal veins and pegmatites during late-stage crystallization of magma, as well as in metamorphic environments where silica-rich fluids cool and precipitate.

Uses & applications

Widely used in electronics (piezoelectric applications), glassmaking, abrasives, river rock landscaping, and as decorative or mineral specimens for collectors.

Geological facts

Milky quartz gets its cloudy white appearance from tiny fluid inclusions (water or gas bubbles) trapped inside the crystal during its formation millions of years ago.

Field identification & locations

Identified in the field by its hardness (scratches glass and steel), lack of cleavage, conchoidal fracture, and milky white color often accented by brownish limonite/hematite staining. Commonly found in gravel beds, mountain regions, pegmatites, and gravel driveways worldwide.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Limonite / Goethite (Iron Ore Mineral nodule)

FeO(OH)·nH2O / FeO(OH)

mineral

Schist

Metamorphic

Septarian Pebble

Septarian nodule / Concretion

sedimentary

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

mineral

Sandstone with Mineral Veining or Crust

Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)

sedimentary