A common type of metamorphic rock with light and dark bands or stripes created by heat and pressure deep in the earth.
From German Gneis, possibly from Old High German gneist (spark), referring to the glittery appearance. German miners named this rock for its sparkly appearance when freshly split.
Gneiss is the second most common rock in Earth's continental crust after granite, and it's how geologists can read the planet's history—the stripes show episodes of intense heat and pressure billions of years ago!
Complete word intelligence in one call. Free tier — 50 lookups/day.