metamorphic

Slate

Slate (Foliated Metamorphic Rock)

AI-generated identification · may be incorrect

Hardness: 2.5-4 on Mohs scale. Color: Grey to dark grey. Luster: Dull to earthy. Texture: Fine-grained with strong slaty cleavage, allowing it to break into flat, thin sheets.

Hardness: 2
Color: Grey to dark grey
Luster: Dull to earthy

Identified July 27, 2026More metamorphic →

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Physical properties

Hardness: 2.5-4 on Mohs scale. Color: Grey to dark grey. Luster: Dull to earthy. Texture: Fine-grained with strong slaty cleavage, allowing it to break into flat, thin sheets.

Formation & geological history

Formed through low-grade regional metamorphism of shale, mudstone, or siltstone under low temperatures and pressures.

Uses & applications

Used for roofing tiles, flooring, electrical insulation, billiard tables, blackboards, and decorative stone work.

Geological facts

Slate is extremely durable and weather-resistant, which is why slate roofs can last over a hundred years.

Field identification & locations

Identified in the field by its distinct planar cleavage, dull surface, ringing sound when tapped, and fine grain size. Common in ancient mountain belts.