Coarse-grained intrusive igneous rock intermediate between granite and gabbro. Contains plagioclase, hornblende, and biotite. Texture: Phaneritic coarse-grained. Rock type: Igneous Intrusive. Grain size: Medium to coarse. Minerals present: Plagioclase, Hornblende, Biotite, Quartz. Formation: Crystallizes slowly from intermediate magma 52-63% SiO₂ within the Earth crust, typically in subduction zone settings. Common geological settings: Found in batholiths and plutons worldwide; common in the Andes, Sierra Nevada, and Scottish Highlands. Common look-alikes and related entries: Granite, Gabbro, Granodiorite.
Granite vs Diorite — Compare observable properties and safer field tests.
Sources, scope & corrections
These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.
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GeoMiner
Last updated
2026-03-30T14:37:20.597252+00:00
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Published; not independently peer-reviewed
Rocks — U.S. National Park Service. Authoritative overview of rock groups, the rock cycle, and geologic processes.
Coarse-grained intrusive igneous rock intermediate between granite and gabbro. Contains plagioclase, hornblende, and biotite.
How can you identify Diorite?
Compare several properties rather than relying on colour alone. This entry records rock type: Igneous Intrusive; texture: Phaneritic coarse-grained; grain size: Medium to coarse; common minerals: Plagioclase, Hornblende, Biotite, Quartz. Confirm an important identification with additional field tests or qualified laboratory work.
How does Diorite form?
Crystallizes slowly from intermediate magma 52-63% SiO₂ within the Earth crust, typically in subduction zone settings.
Where is Diorite commonly found?
Found in batholiths and plutons worldwide; common in the Andes, Sierra Nevada, and Scottish Highlands.
What is Diorite commonly confused with?
Diorite may be confused with Granite, Gabbro, Granodiorite. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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