igneous
Drill core, likely weathered granite or granodiorite
Granite–granodiorite core; chiefly quartz, feldspar, and biotite/hornblende
AI-generated identification · may be incorrectCoarse-grained, pale gray to tan rock with dark mafic specks and rusty brown oxidation; likely Mohs 6–7, vitreous to dull luster, interlocking crystals, and no prominent cleavage as a whole. Some pieces show fracturing and iron-oxide staining.
Identified More igneous →
Explore Drill core, likely weathered granite or granodiorite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Coarse-grained, pale gray to tan rock with dark mafic specks and rusty brown oxidation; likely Mohs 6–7, vitreous to dull luster, interlocking crystals, and no prominent cleavage as a whole. Some pieces show fracturing and iron-oxide staining.
Formation & geological history
This is a human-drilled geological core, not a single hand specimen. The probable granitoid formed from slowly cooled felsic magma, commonly Precambrian to Mesozoic depending on locality; fractures later weathered and oxidized near the surface.
Uses & applications
Drill cores are used for geological mapping, mineral exploration, engineering studies, and resource evaluation; intact granitoid is used as dimension stone, aggregate, and construction material.
Geological facts
The regular cylindrical pieces and labeled core tray indicate diamond drilling. Brown zones may represent weathering, alteration, or iron-rich fracture fillings rather than a separate rock type.
Field identification & locations
Identify granitoid by visible quartz and feldspar grains, pale color, coarse texture, and scattered dark minerals; distinguish it from quartzite by its feldspar-rich, interlocking texture. Exact identification requires a fresh surface, locality data, and petrographic or geochemical testing; common in continental crust and intrusive mountain belts.
