Cello inexpensive wood that has been blackened or "ebonized" to look like ebony, which is much harder and more expensive. Ebonised parts such as tuning pegs may crack or split, and the black surface of the fingerboard will eventually wear down to reveal the lighter wood underneath. Historically, cello strings had cores made out of catgut, which, despite its name is made from sheep or goat intestines which are dried out. Most modern strings used in the 2010s are wound with metallic materials like aluminum, titanium and chromium. Cellists may mix different types of strings on their instruments. The pitches of
Geophone (musical instrument) performance in New York City). Messiaen's wife, Yvonne Loriod, commented that when she and the composer first collected the new instrument from the maker in her car it made a "splendid crescendo" whenever they went round a corner. Messiaen also included the instrument in his only opera, "Saint François d'Assise", which was first performed in Paris 1983. Other works that use the geophone include "Asyla" by Thomas Adès, "…towards a Pure Land" by Jonathan Harvey, and the operas "The Sacrifice" by James MacMillan and "Dark Sisters" by Nico Muhly. Geophone (musical instrument) The geophone is a percussion instrument, invented by