Spiral Mercury is a live album by Pharoah & the Underground, featuring saxophonist Pharoah Sanders, trumpeter Rob Mazurek and drummer Chad Taylor of the Chicago Underground Duo, along with percussionist Mauricio Takara of the São Paulo Underground, bassist Matthew Lux of the Pulsar Quartet, and multi-instrumentalist Guilherme Granado. It was recorded on August 11, 2013, at the Jazz em Agosto Festival in Lisbon, and was released in 2014 by Clean Feed Records.

Pharoah Sanders was an American jazz saxophonist. Known for his overblowing, harmonic, and multiphonic techniques on the saxophone, as well as his use of "sheets of sound", Sanders played a prominent role in the development of free jazz and spiritual jazz through his work as a member of John Coltrane's groups in the mid-1960s, and later through his solo work. He released more than thirty albums as a leader and collaborated extensively with vocalist Leon Thomas and pianist Alice Coltrane, among many others. Fellow saxophonist Ornette Coleman once described him as "probably the best tenor player in the world".