metamorphic
Quartzite (iron-stained, possibly metaconglomeratic)
Quartzite; predominantly recrystallized quartz (SiO₂) with iron-oxide accessory minerals
AI-generated identification · may be incorrectHardness ~7 Mohs; granular, nonfoliated texture; glassy to dull luster; commonly gray, tan, pink, or reddish from hematite/limonite staining. Quartzite lacks cleavage and breaks irregularly or conchoidally; typical specific gravity is ~2.65.
Identified More metamorphic →
Explore Quartzite (iron-stained, possibly metaconglomeratic) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness ~7 Mohs; granular, nonfoliated texture; glassy to dull luster; commonly gray, tan, pink, or reddish from hematite/limonite staining. Quartzite lacks cleavage and breaks irregularly or conchoidally; typical specific gravity is ~2.65.
Formation & geological history
Formed when quartz-rich sandstone was deeply buried and metamorphosed, causing quartz grains to recrystallize and weld together; iron-bearing fluids produced the red-brown coloration. Ages vary widely with the source formation, commonly Precambrian to Paleozoic.
Uses & applications
Used as durable aggregate, roadstone, riprap, building stone, countertops, and decorative landscaping rock; attractive varieties may be cut or polished.
Geological facts
It is generally more resistant to weathering than its parent sandstone and can form prominent ridges and mountain outcrops.
Field identification & locations
Identify it by its uniformly hard, quartz-rich surface: individual sand grains are fused, and a steel file usually cannot scratch it. Common in metamorphic belts worldwide; the image may also include related quartz-rich gravel and other metamorphic rocks.
More like this
