Manhattan schist

Manhattan schist is a type of metamorphic rock prevalent in New York City’s bedrock. Formed from clay-rich mudstones and volcanic ash subjected to intense heat and pressure over millions of years, it exhibits a distinctive layered, coarse-grained appearance with visible mineral grains. This rock is durable and relatively easy to quarry, making it historically valuable for construction, notably in building foundations and skyscrapers. Its mineral composition often includes mica, quartz, and feldspar, giving it a dark, shiny, and foliated look. Manhattan schist is an important geological feature shaping the region’s landscape and development.