Metamorphic rock the foliation is called "gneissosity"), granoblastic (includes granulite, some marbles and quartzite), and hornfelsic (includes hornfels and skarn). Metamorphic rock Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means "change in form". The original rock (protolith) is subjected to heat (temperatures greater than 150 to 200 °C) and pressure ( or more), causing profound physical or chemical change. The protolith may be a sedimentary, igneous, or existing metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. They are classified by
Heat rock in different areas of the tank to create a more even heat gradient, making the pet more liable to move throughout its enclosure. Another popular solution is replacing regular lighting with UV-specific basking lights. http://www.anapsid.org/hotrock.html Heat rock A heat rock is the common name for a type of heating source in enclosures for cold-blooded animals to supply heat, in the form of a false novelty rock plugged into an electrical socket. Keepers may notice that smaller reptiles prefer to rest on the heat rock most of the time, since it provides constant heat. Larger reptiles supplied with heat rocks often