Carbonado Carbonado Carbonado, commonly known as the "black diamond", is the toughest form of natural diamond. It is an impure form of polycrystalline diamond consisting of diamond, graphite, and amorphous carbon. It is found primarily in alluvial deposits in the Central African Republic and in Brazil. Its natural colour is black or dark grey, and it is more porous than other diamonds. Carbonado diamonds are typically pea-sized or larger porous aggregates of many tiny black crystals. The most characteristic carbonados have been found only in the Central African Republic and in Brazil, in neither place associated with kimberlite, the source of
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