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
Musical instrument classification that are rhythmic, a scheme which was probably the first scholarly attempt, while the earlier ones were traditional, folk taxonomies. More usually, instruments are classified according to how the sound is initially produced (regardless of post-processing, i.e., an electric guitar is still a string-instrument regardless of what analog or digital/computational post-processing effects pedals may be used with it). The modern system divides instruments into wind, strings and percussion. It is of Greek origin (in the Hellenistic period, prominent proponents being Nicomachus and Porphyry). The scheme was later expanded by Martin Agricola, who distinguished plucked string instruments, such as guitars, from