More information. A metamorphic rock is a result of a transformation of a pre-existing rock. The original rock is subjected to very high heat and pressure, which cause obvious physical and/or chemical changes.Examples of these rock types include marble, slate, gneiss, schist.ore information. A metamorphic rock is a result of a transformation of a pre-existing rock. The original rock is subjected to very high heat and pressure, which cause obvious physical and/or chemical changes.
Top Definition. pentacle. The pentacle is a five pointed star within a circle, the points representing the four elements (fire, water, earth & air) and ether (spirit) and the circle represents eternity as most pagans believe in the eight-fold year and the spiral dance.. pentacle. a star inside a circle a pentacle is a symbol that pagans and wiccians use. just like the christians have the cross of crusifix. christians usualy think it is a satanic symbol but it isn't. it is. christian: that is a satanic star.
Pentaerythritol tetranitrate. Pentaerythritol tetranitrate (PETN), also known as PENT, PENTA, TEN, corpent, penthrite (orârarely and primarily in Germanâas nitropenta), is the nitrate ester of pentaerythritol, and is structurally very similar to nitroglycerin. Penta refers to the five carbon atoms of the neopentane skeleton.