mineral

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 (Mohs scale), Color: White to orange-brown (due to iron oxide staining), Luster: Vitreous to greasy, Crystal System: Trigonal (Hexagonal), Cleavage: Indistinct (Conchoidal fracture), Specific Gravity: 2.65

Identified March 1, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or as a late-stage mineral in igneous pegmatites. The iron staining occurs when groundwater rich in iron minerals permeates cracks or deposits on the surface over geological time scales. Quartz can be found in rocks dating from the Precambrian to Cenozoic eras.

Uses & applications

Used in the manufacture of glass, ceramics, and electronics (due to piezoelectric properties). Stained quartz like this is often used as landscaping rock, gravel, or collected as a common decorative specimen.

Geological facts

Quartz is the most abundant and varied mineral on the Earth's surface. When quartz appears orange or brownish, it is often nicknamed 'Iron Quartz' or 'Limonite-stained Quartz.' It is physically and chemically very resistant to weathering.

Field identification & locations

Identify in the field by its hardness (it will scratch glass and steel), lack of cleavage, and translucent white color beneath the surface stain. Found worldwide in nearly every geological environment, especially in river beds and weathered hillsides.

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