igneous
Weathered granite or granitic pegmatite fragment
Granite, primarily quartz, alkali feldspar, and plagioclase; exact identification is limited by the photograph
AI-generated identification · may be incorrectCoarse, irregularly crystalline texture with pale gray-white feldspar/quartz and rusty-brown iron-oxide staining; likely Mohs hardness 6–7, vitreous to dull luster, no obvious cleavage as a whole rock, and specific gravity about 2.6–2.7.
Identified More igneous →
Explore Weathered granite or granitic pegmatite fragment in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Coarse, irregularly crystalline texture with pale gray-white feldspar/quartz and rusty-brown iron-oxide staining; likely Mohs hardness 6–7, vitreous to dull luster, no obvious cleavage as a whole rock, and specific gravity about 2.6–2.7.
Formation & geological history
Formed by slow cooling of silica-rich magma deep in the crust, likely during a Precambrian to Phanerozoic intrusive event; the brown surface developed through weathering and oxidation of iron-bearing minerals.
Uses & applications
Granite is widely used as dimension stone, countertops, monuments, aggregate, and decorative material; this weathered fragment has mainly educational or modest collecting value.
Geological facts
The rusty coloration is typically limonite/goethite coating produced by oxidation, not necessarily the rock’s original composition.
Field identification & locations
Identify it by visible interlocking light crystals, quartz’s lack of cleavage, and feldspar cleavage; common in continental mountain belts and glacial deposits worldwide. A fresh broken surface would confirm the texture.
