Amphibolite is a non-foliated metamorphic rock that forms through recrystallization under conditions of high viscosity and directed pressure. It is composed primarily of hornblende (amphibole) and plagioclase, usually with very little quartz. The specimen shown above is about two inches (five centimeters) across. read more
Metamorphic rocks have been modified by heat, pressure, and chemical processes, usually while buried deep below Earth's surface. Exposure to these extreme conditions has altered the mineralogy, texture, and chemical composition of the rocks. There are two basic types of metamorphic rocks. read more
The major types of metamorphic rocks are detailed here, which include regional, contact and mechanical metamorphism. The major types of metamorphic rocks are detailed here, which include regional, contact and mechanical metamorphism. read more