igneous
Diorite
Diorite
Hardness: 6-7 Mohs; Color: Salt and pepper (black and white); Luster: Phaneritic (coarse-grained); Crystal structure: Equigranular; Specific gravity: 2.8-3.0
- Hardness
- 6-7 Mohs
- Color
- Salt and pepper (black and white)
- Luster
- Phaneritic (coarse-grained)
Identified More igneous →
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Physical properties
Hardness: 6-7 Mohs; Color: Salt and pepper (black and white); Luster: Phaneritic (coarse-grained); Crystal structure: Equigranular; Specific gravity: 2.8-3.0
Formation & geological history
Formed by the slow cooling of magma beneath the Earth's surface in volcanic arcs and mountain building zones. It is an intermediate intrusive rock.
Uses & applications
Used as a base material in construction, road building, and as crushed stone. Occasionally polished as a decorative stone or for floor tiles and countertops.
Geological facts
Often called 'salt and pepper rock' due to its contrasting mineral colors. The famous Code of Hammurabi was inscribed on a large black diorite stele.
Field identification & locations
Identify by its phaneritic (visible crystals) speckled appearance and lack of visible quartz compared to granite. Common in roots of mountain ranges.
