Quartz (Milky/Iron-stained)

Physical Properties

Hardness: 7 (Mohs scale), Color: White to tan/orange-brown due to iron oxidation, Luster: Vitreous to greasy, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & Geological History

Formed through the cooling of magma or precipitation from hydrothermal veins. This specimen likely comes from a hydrothermal vein where it grew alongside iron-rich minerals that stained its surface during or after formation.

Uses & Applications

Used in glassmaking, abrasives, electronic oscillators (due to piezoelectricity), and as a gemstone or decorative specimen.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'quarz', which originally meant 'hard'.

Field Identification & Locations

Identify in the field by its ability to scratch glass and its lack of cleavage. Look for the distinct glassy luster and the orange-brown 'rust' staining on its surface. It's found almost globally in igneous, metamorphic, and sedimentary environments.

Identified on: 4/25/2026

Mode: Standard