Metamorphic Rocks

Size

Regional

Coarse - Gneiss

Medium - Schist

Fine - Slate

All formed from regional metamorphism of mudstones and shales.

Contact

Marbles and metaquartzites become coarser the closer they are to the intrusion.

Mudstones/shales

hot = hornfels

warm = spotted slate.

Porphyroblastic

Large crystals e.g. Garnet surounded by finer crystals e.g. micas in a Garnet Mica Schist