Milky and Ferruginous Quartz

Physical Properties

Hardness: 7 on Mohs scale; Color: Milky white to iron-stained peach/orange; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & Geological History

Forms via hydrothermal activity in veins or as a primary constituent in igneous rocks like granite. The peach hue is caused by iron oxide inclusions. Common throughout Earth's crust across all geological ages.

Uses & Applications

Used extensively in glassmaking, electronics (piezoelectric properties), abrasives, and as decorative stone or landscaping material.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'Quarz', which has Slavic origins meaning 'hard'.

Field Identification & Locations

Identified by its ability to scratch glass, lack of cleavage, and waxy to glassy appearance. It is found globally in riverbeds, mountains, and beaches. Collectors should look for the characteristic conchoidal fracture visible on broken surfaces.

Identified on: 4/29/2026

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