mineral

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Opaque white to yellowish-tan due to iron oxide staining; 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-tan due to iron oxide staining
Luster: Vitreous to greasy

Identified March 19, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal fluids or within igneous pegmatites. This specimen likely originated as a hydrothermal vein deposit. The orange/brown coloring is a secondary coating of iron oxides (limonite/goethite) deposited by groundwater.

Uses & applications

Used in glassmaking, abrasives, and as a material in the electronics industry for its piezoelectric properties. Large, pure specimens are popular with mineral collectors and used in lapidary work (cabochons and carvings).

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz gets its cloudiness from tiny trapped bubbles of gas or liquid (fluid inclusions) that formed during the crystal's growth.

Field identification & locations

Identify in the field by its hardness (it will easily scratch glass but cannot be scratched by a steel knife) and its lack of cleavage. Commonly found in mountainous regions, riverbeds, and as veins in granite or metamorphic rocks.

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