mineral

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Translucent white to milky with yellowish-brown iron oxide stains; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal system; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Luster: Vitreous (glassy) to greasy

Identified March 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal solutions or as a primary constituent in igneous rocks like granite. This specimen appears to be a hydrothermal vein fragment, likely from a metamorphic or igneous environment. Geological age varies globally from Archean to Holocene.

Uses & applications

Used in industry as a source of silica for glassmaking, abrasives, and electronics (due to piezoelectric properties). Generally used for decorative landscaping, gravel, or as collector 'rough' material when not gem-quality.

Geological facts

Quartz is one of the most abundant minerals in the Earth's crust. The yellow/brown rust-colored spots are often 'limonite' or 'goethite,' result of iron minerals oxidizing on the surface and in micro-cracks.

Field identification & locations

Identify in the field by its hardness (will scratch glass easily) and lack of cleavage (it breaks into jagged shards like glass). Commonly found in dry creek beds, mountains, and mining tailings worldwide.

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