mineral

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Opaque white to yellowish-brown (due to iron oxide); Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Opaque white to yellowish-brown (due to iron oxide)
Luster: Vitreous to greasy

Identified March 8, 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 shows surface staining from iron oxides (limonite/hematite) deposited by groundwater. Geologically ubiquitous from Precambrian to recent ages.

Uses & applications

Used industrially in glass manufacturing, electronics (piezoelectric properties), and as an abrasive. Low-grade specimens like this are often used for decorative landscaping or geological education.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. 'Milky' quartz gets its white color from millions of tiny fluid inclusions of gas and liquid trapped during crystal growth.

Field identification & locations

Identify in the field by its hardness (it can scratch glass), lack of cleavage, and resistance to weathering. Commonly found in riverbeds, mountains, and as garden stones globally.

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