mineral

Quartz (Iron-stained or Milky)

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale (cannot be scratched by steel). Color: Transparent to milky white with brownish-orange surface staining from iron oxides. Luster: Vitreous (glassy). Crystal Structure: Trigonal/Hexagonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on the Mohs scale (cannot be scratched by steel)
Luster: Vitreous (glassy)

Identified March 21, 2026More mineral →

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Physical properties

Formation & geological history

Formed through hydrothermal processes, crystallization from cooling magma (igneous), or as a sedimentary deposit. It is present in all geological ages from Archean to recent times.

Uses & applications

Used in glassmaking, ceramics, and the electronics industry (piezoelectric properties). Larger, clearer crystals are used in jewelry and gemstone collecting.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is colorless, but the 'rusty' orange color seen here is due to limonite or hematite staining on the surface or within fractures.

Field identification & locations

Identify in the field by its hardness (test against a pocket knife or glass bottle) and lack of cleavage. Found worldwide in veins, geodes, and as a primary component of granite.

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Sandstone (with potential mineral staining/concretions)

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Mineral/Rock

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Metamorphic Rock

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