mineral

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Opaque white to yellowish-brown; 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
Luster: Vitreous to greasy

Identified May 23, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Opaque white to yellowish-brown; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed from silica-rich hydrothermal fluids cooling in veins or cavities within igneous, metamorphic, or sedimentary host rocks. The yellow staining is due to secondary iron oxide (limonite or goethite) infiltration.

Uses & applications

Primarily of interest to casual collectors or used in industrial glassmaking and abrasives when found in large, pure quantities. Small tumbled pieces are used in craft projects and garden decor.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz gets its opaque white appearance from tiny fluid inclusions trapped during the crystal's growth.

Field identification & locations

Identifiable by its inability to be scratched by a steel knife, its lack of cleavage, and its waxy or vitreous luster. This specific piece is a common 'river stone' or vein fragment found globally in gravel beds.

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