Troctolite identification and geology

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• Gabbro
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• Anorthosite

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

2026-03-30T14:38:10.381921+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 Troctolite?

Olivine-plagioclase rock lacking pyroxene. Sometimes called trout rock due to spotted appearance.

How can you identify Troctolite?

Compare several properties rather than relying on colour alone. This entry records rock type: Igneous Intrusive; texture: Phaneritic; grain size: Coarse; common minerals: Plagioclase, Olivine. Confirm an important identification with additional field tests or qualified laboratory work.

How does Troctolite form?

Forms in layered mafic intrusions where olivine and plagioclase co-crystallize without pyroxene.

Where is Troctolite commonly found?

Duluth Complex Minnesota , Rum Scotland , Bushveld; found in layered intrusions.

What is Troctolite commonly confused with?

Troctolite may be confused with Gabbro, Norite, Anorthosite. Compare multiple diagnostic properties because colour and surface appearance can overlap.