igneous
Diorite
Intermediate intrusive igneous rock
AI-generated identification · may be incorrectMohs hardness of 6-7; speckled black and white salt-and-pepper appearance; dull to sub-vitreous luster; composed mainly of plagioclase feldspar and hornblende.
Identified More igneous →
Explore Diorite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Mohs hardness of 6-7; speckled black and white salt-and-pepper appearance; dull to sub-vitreous luster; composed mainly of plagioclase feldspar and hornblende.
Formation & geological history
Forms from the slow cooling of intermediate magma beneath Earth's surface, typically in orogenic belts above subduction zones.
Uses & applications
Commonly used in construction, as crushed stone for road bases, and historically as decorative building stone and ancient Egyptian artifacts.
Geological facts
Often called "pegmatite" incorrectly by novices, diorite's contrasting mineral grains make it exceptionally durable and historically favored for sculpture like the Code of Hammurabi.
Field identification & locations
Identify by its distinct salt-and-pepper texture lacking quartz; found globally in continental roots and major mountain chains.
