What are metamorphic rocks? American Geosciences Institute

Metamorphic rocks are rocks that have become changed by intense heat or pressure while forming. In the very hot and pressured conditions deep inside the Earth’s crust, both sedimentary and igneous rocks can be changed into metamorphic rock. In certain conditions these rocks cool and crystallize usually into bands of crystals. Later they can become exposed on Earth’s surface. One way to tell if a rock sample is metamorphic is to see if the crystals within it are arranged in bands.

Metamorphic Rocks : Metamorphism, Types, Minerals, Formaation

Rock (geology) - Wikipedia

Metamorphic rock - Wikipedia

Metamorphic rock - Wikipedia

The Geoscience Handbook, AGI Data Sheets Fifth Edition

Chapter 2: Section 4 - Metamorphic Rocks and the Geologic History of Your Community

Metamorphic Rocks : Metamorphism, Types, Minerals, Formaation

Colorado Geology - Colorado Geological Survey

Reading: Characteristics of Metamorphic Rocks Geology (modification for Lehman College, CUNY)

Metavolcanic rock - Wikipedia

The Field Description of Metamorphic Rocks, 2nd Edition

Basement Geology of Idaho

Glad You Asked: Igneous, Sedimentary, & Metamorphic Rocks - Utah Geological Survey

Rock: Mineral information, data and localities.