igneous
Diorite (Salt and Pepper Rock)
Diorite
Hardness: 6-7 on Mohs scale. Color: Phaneritic (coarse-grained) mix of black/dark green (amphibole/biotite) and white (plagioclase feldspar). Luster: Sub-vitreous to dull. Crystal structure: Intrusive, phaneritic texture.
- Hardness
- 6-7 on Mohs scale
- Luster
- Sub-vitreous to dull
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Phaneritic (coarse-grained) mix of black/dark green (amphibole/biotite) and white (plagioclase feldspar). Luster: Sub-vitreous to dull. Crystal structure: Intrusive, phaneritic texture.
Formation & geological history
Formed from the slow cooling of silicate magma below the Earth's surface, typically in volcanic arcs or along subduction zones. This specimen appears river-worn or beach-tumbled.
Uses & applications
Used in construction as crushed stone, for floor tiles, granite counters, building facades, and as a durable material for stone carvings and statues.
Geological facts
The famous Code of Hammurabi was inscribed on a massive basalt/diorite stele. It is often referred to as salt and pepper rock due to its contrasting mineral colors.
Field identification & locations
Identify by its 'salt and pepper' look with crystals large enough to see with the naked eye. It contains less quartz than granite. Found in mountainous or volcanic regions where tectonic activity has pushed deep crustal rocks to the surface.
