igneous
Granodiorite
Granodiorite
Hardness: 6-7 (Mohs scale); Color: Salt and pepper/light grey with dark specks; Luster: Dull to sub-vitreous; Crystal structure: Phaneritic (medium-grained); Specific gravity: 2.6-2.73
- Hardness
- 6-7 (Mohs scale)
- Color
- Salt and pepper/light grey with dark specks
- Luster
- Dull to sub-vitreous
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 (Mohs scale); Color: Salt and pepper/light grey with dark specks; Luster: Dull to sub-vitreous; Crystal structure: Phaneritic (medium-grained); Specific gravity: 2.6-2.73
Formation & geological history
Formed through the slow cooling of silica-rich magma deep within the Earth's crust (plutonic). Found in batholiths and mountain ranges worldwide, such as the Sierra Nevada.
Uses & applications
Used primarily as crushed stone for road construction, concrete aggregate, and sometimes as dimensional stone (granite) for countertops and monuments.
Geological facts
The Rosetta Stone was famously carved from granodiorite. It is chemically intermediate between granite and diorite, containing more plagioclase feldspar than orthoclase.
Field identification & locations
Identify in the field by looking for a 'salt and pepper' appearance where white/grey minerals (quartz and feldspar) outweigh black minerals (biotite/hornblende). This specimen shows rounding from water or glacial erosion.
