Slides in Metamorphic Rock
"Meta" comes from the Greek word meaning change. "Morphosis" means form in Greek. So.....
Heat and pressure deep within the Earth's surface can change any rock into metamorphic rock.
Collisions between Earth's plates can push the rock down toward the heat of the mantle. Also pockets of magma rising through the crust can also provide heat to change a rock.
Geologists classify metamorphic rocks by the arrangement of the grains that make up the rocks. There are two categories:
FOLIATED AND NONFOLIATED
A foliated rock has grains that are arranged in parallel layers or bands. The rocks can be thin and flat and may split apart along the bands. Gneiss is an example.
This is an example of a nonfoliated metamorphic rock.
Nonfoliated rocks have grains that are arranged in a random pattern. These rocks do not split into layers. Marble is an example of a nonfoliated metamorphic rock.
Marble is a metamorphic rock. Marble has a fine, even grain and is relatively easy to cut into thin slabs.
Marble is used by architects and sculptors for many buildings and statues. The Taj Mahal is made of gleaming white marble.
Slate is foliated and splits easily into flat pieces that can be used for many things.
Slate is used for flooring, roofing, outdoor walkways, or chalkboards.