metamorphic

Foliated amphibolite (likely augen or spotted amphibolite)

Amphibolite, composed chiefly of hornblende and plagioclase; exact identification requires close examination

AI-generated identification · may be incorrect

Dark gray-green, fine- to medium-grained rock with pale, lens-shaped mineral patches and weak foliation. Typical amphibolite minerals have Mohs hardness around 5–6; the pale patches may be feldspar or quartz.

Identified September 26, 2026More metamorphic →

Explore Foliated amphibolite (likely augen or spotted amphibolite) in the encyclopedia →

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Physical properties

Formation & geological history

Forms when basaltic or gabbroic rocks undergo medium- to high-grade metamorphism, commonly during mountain building. Its age cannot be determined from the photograph.

Uses & applications

Used locally as dimension stone, aggregate, or landscaping stone; distinctive pieces may be collected or polished.

Geological facts

Amphibolite is named for amphibole minerals, especially hornblende. The pale lenses could reflect mineral segregation or deformation, but the image alone cannot establish their composition.

Field identification & locations

Look for a dense, dark rock with amphibole-rich texture and lighter feldspar-rich bands or lenses; amphibolites occur in metamorphic belts worldwide. A hand lens and fresh surface would improve identification.