metamorphic
Iron-stained quartzite or silicified breccia
Quartz-rich rock dominated by microcrystalline quartz (SiO₂), with iron oxides/hydroxides such as hematite and goethite
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; tan, gray, reddish-brown, and yellow coloration with earthy to glassy luster. Massive, granular texture; quartz-rich areas lack obvious cleavage and commonly fracture conchoidally. The image is insufficient for a definitive species-level identification.
Identified More metamorphic →
Explore Iron-stained quartzite or silicified breccia in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness about 6.5–7 Mohs; tan, gray, reddish-brown, and yellow coloration with earthy to glassy luster. Massive, granular texture; quartz-rich areas lack obvious cleavage and commonly fracture conchoidally. The image is insufficient for a definitive species-level identification.
Formation & geological history
Likely formed by metamorphism or silica replacement of a sandstone, breccia, or altered host rock, with later oxidation producing the red-yellow iron staining. Exact geological age and locality cannot be determined visually.
Uses & applications
Generally used as a decorative or lapidary rough, aggregate, or collector specimen; attractive pieces may be cut or polished, but it has little industrial value compared with uniform quartzite.
Geological facts
The rusty colors typically reflect hematite, limonite, and goethite coatings or cement. A steel-file scratch test and dilute hydrochloric-acid test can help distinguish quartz-rich rock from softer carbonate material.
Field identification & locations
Common in hydrothermal veins, weathered iron-rich zones, quartzite terrains, and silicified breccias. It should scratch ordinary glass and should not noticeably fizz in dilute acid; a locality label is needed for a reliable identification.
More like this
