1) Gneiss is a common metamorphic rock formed from igneous or sedimentary rocks under high-grade regional metamorphism. It is medium- to coarse-foliated with little mica or other platy minerals.
2) Marble is a non-foliated metamorphic rock formed from limestone composed primarily of calcite. It is widely used as a building material.
3) Migmatite forms under extreme heat during metamorphism, where partial melting occurs in pre-existing rocks resulting in a mixture of newly crystallized and older resistant materials.