mineral

Ferruginous Quartz

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Hardness: 7 (Mohs scale), Color: Rusty brown, orange, and tan. Luster: Vitreous to dull. Crystal structure: Hexagonal. Cleavage: None (Conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 (Mohs scale), Color: Rusty brown, orange, and tan
Color: Rusty brown, orange, and tan
Luster: Vitreous to dull

Identified June 6, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: Rusty brown, orange, and tan. Luster: Vitreous to dull. Crystal structure: Hexagonal. Cleavage: None (Conchoidal fracture). Specific Gravity: 2.65.

Formation & geological history

Formed through the deposition of silica in hydrothermal veins or sedimentary environments where iron oxides (hematite or goethite) permeate the quartz matrix, providing the distinct rusty coloration.

Uses & applications

Used primarily as decorative garden stones, in lapidary work for tumbled stones, and as metaphysical or collector specimens. Low-grade specimens are used in general construction fill.

Geological facts

Also known as Eisenkiesel or Iron Quartz, this material is essentially rock crystal or milky quartz that has been naturally stained or coated by iron during its formation process.

Field identification & locations

Identify in the field by its high hardness (it will scratch glass/steel) and the presence of waxy or glassy translucent patches beneath a crust of earthy iron oxide. Commonly found in riverbeds and mountainous regions globally.

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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

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic