Ferruginous Quartz

Physical Properties

Hardness: 7 (Mohs scale); Color: Yellowish-brown to orange from iron staining, translucent; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Formation & Geological History

Formed from hydrothermal solutions or cooling magma rich in silica. The yellow/brown color is due to the infiltration of iron-rich groundwater or limonite/hematite inclusions during or after crystallization.

Uses & Applications

Used primarily as decorative stones, in landscaping, and as a collector's specimen. High-quality quartz is used in electronics and glass-making.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Iron-stained quartz is often mistaken for citrine, though citrine's color is within the crystal lattice rather than a surface staining or inclusion.

Field Identification & Locations

Identify in the field by its hardness (it will scratch glass), lack of cleavage, and the characteristic conchoidal fracture. Commonly found in riverbeds, gravel pits, and mountain ranges globally.

Identified on: 4/15/2026

Mode: Standard