Chalk is a song by The Prayer Chain. It was written during the sessions for the album Mercury, though did not appear on the final release. It was included on their compilation of outtakes called Mercurios as well as the rarities/live album Antarctica.

The song also appeared on the original draft of Mercury, later released as Humb.

Chalk is the only Prayer Chain song where drummer Wayne Everett is credited as the sole lyricist. One of the intentions when recording the song was to avoid drum fills.

A live version of the song appears on Live At The Strand, a compilation of various artists. Cush also played the song live on occasion.

Everett originally wrote the lyrics for a different song which eventually appeared on his solo album KingsQueens. During the Mercury sessions, it morphed into the version heard on Mercurios & Antarctica.
