mineral

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Hardness: 7 (Mohs scale); Color: Yellow to rusty orange/brown; Luster: Vitreous (glassy) to dull; Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: ~2.65.

Hardness: 7 (Mohs scale)
Color: Yellow to rusty orange/brown
Luster: Vitreous (glassy) to dull

Identified April 5, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 7 (Mohs scale); Color: Yellow to rusty orange/brown; Luster: Vitreous (glassy) to dull; Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: ~2.65.

Formation & geological history

Formed through the precipitation of silica from hydrothermal fluids or slow cooling of magma. The distinct orange/brown coloration is a result of later iron-oxide staining (limonite or hematite) leaching into cracks or coating the surface over thousands of years.

Uses & applications

Common specimens are used as landscape stones or for metaphysical/collector interest. High-quality varieties can be cut as semi-precious gemstones (often called 'Iron Quartz' or 'Golden Healer').

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Ferruginous quartz specifically gets its 'rusty' look because iron is so prevalent in the environment and easily stains quartz's micro-fractures.

Field identification & locations

Identify in the field by its hardness (will scratch glass), lack of cleavage, and the characteristic rusty-orange coating or internal staining. It is commonly found in gravel pits, creek beds, and mountainous regions worldwide.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral