"The Marble Index" avant-garde style distanced Nico from rock and pop. When an interviewer pointed out the contrast between "Chelsea Girl" and "The Marble Index", Nico said that the latter was ""not" supposed to be noise, because most pop music to me is noise, alright?" According to John Cale, the album "makes more sense in terms of advancing the modern European classical tradition than it does as folk or rock music". With Nico's compositions based around one or two chords, Cale decided to avoid drone and raga (Eastern music common on the West Coast at the time) in favor of a European classical approach in his arrangements. The resulting sound has been compared with Germanic folk music, Gregorian chant, medieval music such as madrigals, European avant-garde, Romanticism, and the music of Richard Wagner.