metamorphic

Slate / Greenschist

Foliated Metamorphic Rock (Greenschist/Slate)

AI-generated identification · may be incorrect

Mohs hardness: 2.5-4; Color: Dark greyish-green to charcoal; Luster: Dull to pearly/satin; Texture: Fine-grained, foliated with slaty or schistose cleavage; Specific gravity: 2.7-2.9.

Hardness: 2
Color: Dark greyish-green to charcoal
Luster: Dull to pearly/satin

Identified July 25, 2026More metamorphic →

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Physical properties

Mohs hardness: 2.5-4; Color: Dark greyish-green to charcoal; Luster: Dull to pearly/satin; Texture: Fine-grained, foliated with slaty or schistose cleavage; Specific gravity: 2.7-2.9.

Formation & geological history

Formed by low-grade regional metamorphism of shale, clay, or mafic volcanic rocks under directed pressure and mild temperature. Typically dates from Precambrian to Cenozoic mountain-building periods.

Uses & applications

Used historically and modernly in roofing tiles, flooring, billiard tables, blackboards, and decorative landscaping stones.

Geological facts

Slate breaks easily along flat, parallel planes of foliation due to alignment of microscopic sheet silicates like chlorite and muscovite.

Field identification & locations

Identified by its distinctive fissility (splits into thin sheets), dull sheen, fine grain, and characteristic dark greenish-grey color. Commonly found in regions with ancient or active collisional mountain belts.