mineral

Quartz (Milky or Iron-Stained)

Silicon Dioxide (SiO2)

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

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

Identified March 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. Often found in pegmatites and hydrothermal ore deposits. It can occur in geological formations ranging from billions of years old to relatively recent volcanic systems.

Uses & applications

Used widely in manufacturing glass, ceramics, and electronics (due to piezoelectric properties). In crushed form, used as an abrasive or in construction. Some stained specimens are collected for lapidary work or as garden decoration.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is perfectly clear; the 'milky' look of this specimen is caused by tiny inclusions of gas or liquid trapped during crystal growth. The yellow staining is likely 'limonite' or iron oxide.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife and its lack of cleavage. It is found globally, common in riverbeds and mountainous terrain. Collectors should look for distinct crystal faces or vugs, though this specimen appears to be massive/cryptocrystalline quartz.

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