mineral

Quartz (Milky/Iron-stained)

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale. Color: White to translucent with yellowish-red iron staining. Luster: Vitreous (glassy) to greasy. Crystal structure: Hexagonal/Trigonal. Cleavage: Indistinct/Conchoidal fracture. Specific gravity: 2.65.

Hardness: 7 on the Mohs scale
Color: White to translucent with yellowish-red iron staining
Luster: Vitreous (glassy) to greasy

Identified March 16, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal solutions cooling in rock veins or through crystallization from cooling magma (igneous). This specimen likely originated in a hydrothermal vein and has been weathered, contributing to its rounded shape and surface staining.

Uses & applications

Used extensively in glassmaking, electronics (piezoelectric properties), abrasives, and as a common component in concrete and construction aggregates. Small raw pieces like this are often collected by hobbyists or used in landscaping.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is clear; the 'milky' appearance of this specimen is caused by tiny fluid inclusions trapped during crystal growth.

Field identification & locations

Identify in the field by its ability to scratch glass and its lack of cleavage (it breaks in irregular, curved 'conchoidal' fractures). It is found worldwide in mountains, riverbeds, and beaches. Collectors should look for distinct crystal faces, which this tumbled specimen lacks.