greenschist

Greenschist is a type of metamorphic rock formed under moderate heat and pressure from pre-existing rocks, typically rich in minerals like chlorite, epidote, and actinolite. Its name comes from its characteristic greenish color. These conditions cause the original rock to undergo mineral changes without melting, resulting in a foliated (layered) texture. Greenschist is often associated with regional metamorphism found in mountain-building zones and is commonly linked to geological processes that shape the Earth's crust. Its distinctive appearance and mineral composition make it significant in geology and sometimes as a decorative stone.