igneous
Diorite
Diorite
Hardness: 6-7 on Mohs scale. Color: Salt-and-pepper (mottled black and white/grey). Luster: Phaneritic (medium to coarse-grained crystals). Crystal Structure: Intrusive igneous. Specific Gravity: 2.8-3.0.
- Hardness
- 6-7 on Mohs scale
- Color
- Salt-and-pepper (mottled black and white/grey)
- Luster
- Phaneritic (medium to coarse-grained crystals)
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Salt-and-pepper (mottled black and white/grey). Luster: Phaneritic (medium to coarse-grained crystals). Crystal Structure: Intrusive igneous. Specific Gravity: 2.8-3.0.
Formation & geological history
Formed through the slow cooling of magma beneath the Earth's surface in volcanic arcs and mountain building zones (orogeny). It is an intrusive igneous rock intermediate between granite and gabbro.
Uses & applications
Used primarily as crushed stone for road construction and drainage. Also used as dimension stone for building facades, tiling, and occasionally for statues and cemetery markers.
Geological facts
The famous Code of Hammurabi was inscribed on a seven-foot-tall black diorite stele. In ancient Egypt, it was highly valued for sculpture due to its extreme hardness and durability.
Field identification & locations
Identified by its medium-grained, equigranular texture lacking visible quartz. It contains more dark minerals than granite but fewer than gabbro. Found in continental crust near subduction zones, such as the Andes Mountains.
