right|thumb|Glass harmonica: spinning glass disks (bowls) on a common shaft are arranged with the lower notes (larger disks) to the left and higher notes (smaller disks) to the right.
thumb|right|A glass harp being played in [[Rome, Italy. The rims of wine glasses filled with water are rubbed by the player's fingers to create the notes.]]
thumb|The [[Cristal Baschet]]
A crystallophone is a musical instrument that produces sound from glass.
One of the best known crystallophones is the glass harmonica, a set of rotating glass bowls which produce eerie, clear tones when rubbed with a wet finger. Musical glasses, the glass harp, were documented in Persia in the 14th century. The "ethereal" quality of instruments such as the glass harmonica exemplified the ' and for a while, "the instrument was extraordinarily popular...[but] About 1830 the instrument fell into oblivion." sexologist James Graham uses the glass harmonica for musical therapy purposes.
Benjamin Franklin was inspired to create his glass harmonica in 1763 after attending a recital performed on musical glasses in London in 1761.