metamorphic

Slate

Metamorphic Pelitic Rock

AI-generated identification · may be incorrect

Hardness: 3-4 on the Mohs scale, Color: Grey, black, green, or red, Luster: Dull to sub-mat, Crystal Structure: Microcrystalline, Cleavage: Excellent slaty cleavage, Specific Gravity: 2.6-2.8

Identified August 6, 2026More metamorphic →

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Physical properties

Hardness: 3-4 on the Mohs scale, Color: Grey, black, green, or red, Luster: Dull to sub-mat, Crystal Structure: Microcrystalline, Cleavage: Excellent slaty cleavage, Specific Gravity: 2.6-2.8

Formation & geological history

Formed by low-grade regional metamorphism of mudstone or shale, typically originating in tectonic compression environments over millions of years.

Uses & applications

Used in roofing, flooring, billiards tables, blackboards, and decorative aggregate.

Geological facts

Slate's exceptional ability to split into thin, durable sheets has made it a preferred construction and writing material for centuries.

Field identification & locations

Identify by its distinctive parallel foliation (slaty cleavage) and fine-grained texture. Commonly found in mountainous regions and areas with ancient tectonic activity.