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 Shield Rock Heat Shield Rock Heat Shield Rock is a basketball-sized iron-nickel meteorite found on Mars by the Mars rover "Opportunity" in January 2005. The meteorite was formally named Meridiani Planum meteorite by the Meteoritical Society in October, 2005 (meteorites are always named after the place where they were found). "Opportunity" encountered the meteorite entirely by chance, in the vicinity of its own discarded heat shield (hence the name). "Opportunity" had been sent to examine the heat shield after exiting the crater Endurance. This was the first meteorite found on another planet and the third found on another Solar System body —