igneous
Diorite
Phaneritic intermediate igneous rock
AI-generated identification · may be incorrectHardness 6-7 on Mohs scale, salt-and-pepper appearance due to contrasting white plagioclase feldspar and dark amphibole or biotite, sub-to-euhedral crystal structure with no cleavage as a bulk rock.
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Physical properties
Hardness 6-7 on Mohs scale, salt-and-pepper appearance due to contrasting white plagioclase feldspar and dark amphibole or biotite, sub-to-euhedral crystal structure with no cleavage as a bulk rock.
Formation & geological history
Formed from the slow cooling of intermediate magma beneath the Earth's crust, typically associated with convergent plate boundaries and continental arcs.
Uses & applications
Commonly used in construction as crushed stone for road bases, and polished for building facades, decorative facing stones, and dimension stone.
Geological facts
Often historically referred to as 'granite' in commercial trade despite having different mineralogy. Ancient Egyptian sculptors frequently used diorite for statues due to its extreme toughness.
Field identification & locations
Identify in the field by its distinct intermediate composition featuring roughly equal proportions of dark and light minerals with a coarse-grained texture. Found globally in major mountain belts and subduction zones.
