Here's a breakdown:

* Shale: A sedimentary rock formed from compacted mud and clay.

* Metamorphism: The process of transforming existing rocks (like shale) through heat and pressure.

* Slate: A fine-grained metamorphic rock formed from shale. It has a distinct, often layered, appearance and is often used for roofing and flooring.

Here's a simplified way to think about it:

* Shale (Sedimentary) -> Heat & Pressure -> Slate (Metamorphic)