Using rocks as instruments goes back a very long time. Known as "rock gongs" they were rocks which could be struck and produced a melodious resonant sound, and were used in Africa. In Vietnam they built a form of "Lithophones" or musical instrument built from rocks, and some of these instruments date back nearly 2000 years. In Korea they built Pyeongyeong, while prehistoric lithophone stones have been found in Orissa, India. All of which points to the fact that when humans find stones that can make music, they tend to take note.
Near Butte Montana, just such stones exist. Part of the edge of the Boulder Batholith, and found in a large jumbled pile of boulders, the rocks in this unique geologic formation chime melodically when tapped lightly with a crescent wrench or mallet.
It is believed that the ringing is a combination of the composition of the rock and the way the joining patterns have developed as the rocks have eroded away, though ultimately a concrete scientific explanation has yet to be arrived at. Curiously, if a boulder is removed from the pile, it no longer rings.
Slightly different pitches and timbres emanate from thousands of rocks in the formation, and in theory Butte's Ringing Rocks could form the basic ostinato for the "Music of the Spheres."(Musica Universalis)