Experimental petrology of oxides to replicate the chemistry of the rock/system in question) in an apparatus capable of creating and sustaining high pressures and temperatures such as a Diamond anvil cell. In general, it is ideal if the enclosing capsule is relatively nonreactive, such as diamond or platinum/gold alloys . Experimental igneous petrology is the subset of experimental petrology concerned with quantifying the behavior of magmas and their associated igneous rocks at depth. Standard procedure generally involves the creation of a synthetic magma (often corresponding to a real world analog) which is then cooled to a target temperature. After crystallization, the products
What Is and What Should Never Be descending riff [of "What Is and What Should Never Be"] is amazing: It's like a bow is being drawn back, and then it releases. The rhythm of the vocals is almost like a rap. It's insane — one of their most psychedelic songs." This was also one of the first songs recorded by the band for which Robert Plant received writing credit. According to rock journalist Stephen Davis, the author of the Led Zeppelin biography "Hammer of the Gods: The Led Zeppelin Saga", the lyrics for this song reflect a romance Plant had with his wife's younger sister. "What Is