Granite may have more alkali feldspar, whereas a granite derived from partial melting of metaigneous rocks may be richer in plagioclase. It is on this basis that the modern "alphabet" classification schemes are based. The letter-based Chappell & White classification system was proposed initially to divide granites into I-type (igneous source) granite and S-type (sedimentary sources). Both types are produced by partial melting of crustal rocks, either metaigneous rocks or metasedimentary rocks. M-type granite was later proposed to cover those granites that were clearly sourced from crystallized mafic magmas, generally sourced from the mantle. However, this proposal has been rejected by
This Is What Rock n' Roll Looks Like week, the song went up two spots, peaking at number forty-four. The following two weeks, "This Is What Rock n' Roll Looks Like" remained stationary at number forty-four on the weeks ending August 1, 2011 and August 8, 2011, respectively. A music video for "This Is What Rock n' Roll Looks Like" was shot and directed by Sanaa Hamri at Citrus College in Glendora, California. Porcelain Black discussed the idea behind the music video for "This Is What Rock n' Roll Looks Like" with AOL's Carlos Ramirez, stating it was based on real life experiences. After Porcelain Black's mother had