| Name: | Slate |
| Derivation: | From "esclate" (Old French) |
| Description: | Opaque grey rock which splits easily into thin slabs. In fact, there is quite a range of slate colours. All these specimens come from the Welsh slate museum at Llanberis, near Snowdon, where you can see 11 colours of slate. |
Slates have a single perfect cleavage (slatey cleavage), which means that it is possible to split slate into very thin slabs. This means that it makes a very good roofing material, waterproof and light. See the photograph for examples.