Schist

“Sheets of shimmer”

Metamorphic

Schist is a medium-grade metamorphic rock defined by its schistosity — visible, parallel alignment of platy minerals that gives it a shimmery, layered appearance. It forms when shale or mudstone undergoes more intense metamorphism than what produces slate.

Composition

mica (muscovite or biotite), quartz, garnet, chlorite, talc

Where Found

Manhattan (USA — the island sits on schist), Scottish Highlands, Alps, Otago (New Zealand)

Mohs Hardness

3.5-5

Fun Fact

Manhattan's famous skyscrapers are built on a foundation of Manhattan Schist — a 450-million-year-old bedrock that can support massive structures.