mineral

Quartz (Iron-Stained)

Crystalline Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: Translucent to opaque orange/yellow/brown due to iron oxide impurities (limonite/hematite), Luster: Vitreous to greasy, Crystal structure: Hexagonal/trigonal, Cleavage: None (conchoidal fracture).

Identified June 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or as a component of igneous rocks. The staining occurs when iron-rich groundwater permeates cracks in the quartz or when iron minerals oxidize on the surface over geological time.

Uses & applications

Industrial uses (electronics, glass-making), decorative stone, and mineral specimens for collectors.

Geological facts

Quartz is one of the most abundant minerals in Earth's crust. Specimens found in France, particularly from regions like the Alps or Massif Central, often show beautiful iron-stained patinas or 'limonite' coatings.

Field identification & locations

Identify in the field by its hardness (it scratches glass) and lack of cleavage. It is extremely common in French riverbeds, mountainous terrains, and agricultural fields as discarded cobbles.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

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