How can you identify Diabase?

Compare several properties rather than relying on colour alone. This entry records rock type: Igneous Intrusive/Hypabyssal; texture: Ophitic intergrown plagioclase and pyroxene; grain size: Medium; common minerals: Plagioclase, Augite, Olivine, Magnetite. Confirm an important identification with additional field tests or qualified laboratory work.

What is Diabase commonly confused with?

Diabase may be confused with Basalt, Gabbro, Diorite. Compare multiple diagnostic properties because colour and surface appearance can overlap.

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Diabase identification and geology

Medium-grained mafic intrusive rock also called dolerite with ophitic texture. Forms sills and dikes. Texture: Ophitic intergrown plagioclase and pyroxene. Rock type: Igneous Intrusive/Hypabyssal. Grain size: Medium. Minerals present: Plagioclase, Augite, Olivine, Magnetite. Formation: Crystallizes from mafic magma in shallow intrusions sills and dikes at intermediate cooling rates. Common geological settings: Palisades Sill New Jersey , Great Whin Sill England ; found worldwide as dikes and sills. Common look-alikes and related entries: Basalt, Gabbro, Diorite.

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Basalt
Gabbro
Diorite

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.

Editorial owner: GeoMiner
Last updated: 2026-03-30T14:38:11.066719+00:00
Review status: Published; not independently peer-reviewed

Rocks — U.S. National Park Service. Authoritative overview of rock groups, the rock cycle, and geologic processes.
Can you identify my rock or mineral? — U.S. Geological Survey. Identification limitations and routes to in-person professional verification.

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Common questions

What is Diabase?: Medium-grained mafic intrusive rock also called dolerite with ophitic texture. Forms sills and dikes.
How can you identify Diabase?: Compare several properties rather than relying on colour alone. This entry records rock type: Igneous Intrusive/Hypabyssal; texture: Ophitic intergrown plagioclase and pyroxene; grain size: Medium; common minerals: Plagioclase, Augite, Olivine, Magnetite. Confirm an important identification with additional field tests or qualified laboratory work.
How does Diabase form?: Crystallizes from mafic magma in shallow intrusions sills and dikes at intermediate cooling rates.
Where is Diabase commonly found?: Palisades Sill New Jersey , Great Whin Sill England ; found worldwide as dikes and sills.
What is Diabase commonly confused with?: Diabase may be confused with Basalt, Gabbro, Diorite. Compare multiple diagnostic properties because colour and surface appearance can overlap.

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Diabase identification and geology

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Sources, scope & corrections

Common questions