Petrography rock was affixed to a microscope slide and then ground so thin that light could be transmitted through mineral grains that otherwise appeared opaque. The position of adjoining grains was not disturbed, thus permitting analysis of rock texture. Thin section petrography became the standard method of rock study. Since textural details contribute greatly to knowledge of the sequence of crystallization of the various mineral constituents in a rock, petrography progressed into petrogenesis and ultimately into petrology. It was in Europe, principally in Germany, that petrography advanced in the last half of the nineteenth century. The macroscopic characters of rocks, those
(What Is) Love? (What Is) Love? "(What Is) Love?" is a song recorded by American entertainer Jennifer Lopez. Originally entitled "What Is Love?", the song appeared on the soundtrack to "The Back-up Plan" (2010), a film in which Lopez stars. The song was later included on Lopez's seventh studio album "Love?" (2011), as the album's title track. "(What Is) Love?" is a midtempo electropop song written by Diana "Wynter" Gordon, with the song's producer Emile "D'Mile" Dernst II. The song is about "not knowing what love is," according to Gordon. A remix of "(What Is) Love?", entitled "What Is Love? Part II", was