Quartz (Milky/Iron-stained)

Physical Properties

Hardness: 7 on Mohs scale; Color: Semi-translucent white with yellow/orange iron staining; Luster: Vitreous (glassy) to waxy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & Geological History

Formed through the cooling of silica-rich magma or from hydrothermal veins. This specific piece appears to be a water-worn or weathered pebble likely from a riverbed or sedimentary deposit of much older igneous origin.

Uses & Applications

Used in glassmaking, abrasives, and electronics (due to piezoelectric properties). This specific rough form is used as landscaping stone or for amateur lapidary (tumbling).

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is clear, but impurities like iron (seen here as yellow staining) or trapped gas bubbles create different varieties.

Field Identification & Locations

Identify in the field by its hardness (it will scratch glass but not be scratched by a steel knife) and its lack of cleavage planes. Found globally in almost all geological environments.

Identified on: 4/13/2026

Mode: Standard