The New Grove Dictionary of Music and Musicians is widely used by college music students and is regarded by most (for better or for worse) as the unimpeachable source of all musical knowledge. In my studies for upcoming doctoral comprehensive exams, I ran across this in the “Flute” article:
Materials used for the tube and mechanism include nickel-silver, sterling silver, gold and platinum, while the springs are usually of tempered steel or phosphor bronze, occasionally of gold or another metal. The choice of material, especially for the head joint, influences the flute’s tone: wooden flutes produce a rich tone with a very full fortissimo in the lower register; metal flutes produce a limpid, flexible tone with great carrying power and also allow the player very sensitive control over the tone-colour; gold produces a mellow sound while silver is more brilliant. To achieve a combination of these qualities a head joint of wood or gold is sometimes fitted to a tube of silver.
The idea of different materials having different sounds is, of course, seen as conventional wisdom by flutists (and indeed by wind players in general), but it flies in the face of 100 years of acoustical science.