mineral

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: semi-translucent with reddish-brown iron staining; Luster: vitreous (glassy) to greasy; Crystal system: Hexagonal/Trigonal; Cleavage: none (conchoidal fracture).

Hardness: 7 on Mohs scale
Color: semi-translucent with reddish-brown iron staining
Luster: vitreous (glassy) to greasy

Identified July 5, 2026More mineral →

Explore Quartz (Iron-stained) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale; Color: semi-translucent with reddish-brown iron staining; Luster: vitreous (glassy) to greasy; Crystal system: Hexagonal/Trigonal; Cleavage: none (conchoidal fracture).

Formation & geological history

Formed in hydrothermal veins or as a primary constituent of igneous and metamorphic rocks. The reddish tint comes from oxidized iron (limonite or hematite) leaching into micro-fractures in the quartz.

Uses & applications

Commonly used as abrasive, in the manufacture of glass and ceramics, and in electronic oscillators and watches. Rough specimens are popular for amateur collecting.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Iron-stained quartz is often mistaken for carnelian or sunstone by beginners due to its reddish hue.

Field identification & locations

Identify in the field by its hardness (will scratch glass) and lack of cleavage. Look for the characteristic conchoidal fracture which looks like wavy chips in a piece of glass.