igneous
Pink-and-black granite
Biotite-bearing granite, chiefly quartz, feldspar, and biotite mica
AI-generated identification · may be incorrectCoarse-grained, mottled pink, gray, and black rock with interlocking crystals; quartz and feldspar give a glassy to dull luster, while biotite is platy. Hardness is about 6–7 Mohs; cleavage occurs in feldspar and mica, but the rock has no overall cleavage.
Identified More igneous →
Explore Pink-and-black granite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Coarse-grained, mottled pink, gray, and black rock with interlocking crystals; quartz and feldspar give a glassy to dull luster, while biotite is platy. Hardness is about 6–7 Mohs; cleavage occurs in feldspar and mica, but the rock has no overall cleavage.
Formation & geological history
An intrusive igneous rock formed when silica-rich magma cooled slowly deep underground, allowing large crystals to grow. Its exact geological age cannot be determined from the image and may range from Precambrian to younger continental granite.
Uses & applications
Widely used as building stone, monuments, countertops, tiles, curbing, and crushed aggregate; attractive pieces may be polished for architectural or decorative use.
Geological facts
The pink color usually comes from potassium feldspar, gray areas from quartz or plagioclase, and black flakes from biotite. The swirling appearance may reflect deformation or flow in the original magma.
Field identification & locations
Identify it by visible interlocking crystals, abundant pink feldspar, gray quartz, and black mica; it is common in continental mountain belts and granite quarries worldwide. A hand lens and fresh broken surface improve identification.
