igneous
Granodiorite
Granodiorite (Intermediate intrusive igneous rock)
Hardness: 6-7 on Mohs scale. Color: Salt-and-pepper (gray, white, black, with occasional pinkish hue). Luster: Phaneritic (crystalline). Texture: Medium to coarse-grained. Specific Gravity: 2.6-2.7. Primarily composed of plagioclase feldspar, quartz, and biotite/hornblende.
- Hardness
- 6-7 on Mohs scale
- Luster
- Phaneritic (crystalline)
Identified More igneous →
Explore Granodiorite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 on Mohs scale. Color: Salt-and-pepper (gray, white, black, with occasional pinkish hue). Luster: Phaneritic (crystalline). Texture: Medium to coarse-grained. Specific Gravity: 2.6-2.7. Primarily composed of plagioclase feldspar, quartz, and biotite/hornblende.
Formation & geological history
Formed through the slow cooling of magma deep beneath the Earth's surface (plutonic). It is intermediate between granite and diorite. Commonly formed in volcanic arcs above subduction zones during various geological eras from the Precambrian to Cenozoic.
Uses & applications
Extensively used in construction as crushed stone for road base, building stone, and decorative facades. It is often sold commercially as 'granite' for kitchen countertops and floor tiles due to its durability.
Geological facts
Granodiorite is the rock that makes up the famous Rosetta Stone. It is a major component of batholiths, such as the Sierra Nevada Batholith in California. It contains more plagioclase feldspar than orthoclase feldspar, which distinguishes it from true granite.
Field identification & locations
Identify in the field by its interlocking crystalline texture containing both light (quartz/feldspar) and dark (biotite/amphibole) minerals. Plagioclase feldspar may show striations. Found in mountainous or shield regions. Useful for determining tectonic history of an area.
