1. Slate: Formed from shale under low-grade metamorphism. It has a fine-grained, slaty cleavage that allows it to split into thin, flat sheets.

2. Schist: Formed from a wider range of parent rocks under medium-grade metamorphism. It has a more pronounced foliation than slate, with visible mineral grains arranged in layers.

3. Gneiss: Formed from a wide range of parent rocks under high-grade metamorphism. It has a distinct banding of light and dark minerals, which creates a more coarse-grained foliation than schist.