metamorphic

Weathered iron-rich quartz vein in altered host rock

Goethite–hematite limonite with quartz and iron-oxide alteration

AI-generated identification · may be incorrect

Dark brown, fine-grained and strongly foliated host rock contains rusty orange-brown iron oxides and translucent quartz-like material. Approximate hardness 5–7 for quartz, 4–5 for goethite/limonite; earthy to submetallic luster, no obvious cleavage, and variable density.

Identified September 13, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely formed when silica- and iron-bearing fluids filled fractures in a metamorphosed or strongly altered rock, followed by weathering and oxidation. The precise age and locality cannot be determined from the photograph.

Uses & applications

Primarily a collector specimen; iron-rich material may have historical use as pigment or low-grade iron ore, while quartz is industrially useful but this specimen is not suitable for construction.

Geological facts

The orange coloration is characteristic of hydrated iron oxides such as limonite/goethite, while black areas may contain hematite or manganese oxides. The glossy banded surfaces could also reflect polished or naturally slickensided fracture faces.

Field identification & locations

Look for a heavy, rusty specimen with red-brown streak, quartz veining, and possible magnetism if magnetite is present. Common in oxidized fracture zones, hydrothermal veins, and weathered mineral deposits worldwide; locality information is essential for a more exact identification.