The humble guitar pick, or plectrum, has a story that dates back to the start of recorded history. The ancient Greeks used a 'plēktron' (a handle with a short blade of ivory, bone, or wood) to pluck the lyre. Stringed instruments were subsequently played with feather quills until the discovery of tortoiseshell in the 19th century, which was then used until sea turtles were hunted almost to extinction.
D'Andrea company introduced celluloid picks in 1922, which were the standard until Jim Dunlop introduced Tortex (a tortoiseshell substitute) in 1981. Today, guitar picks can be made from just about anything, including polycarbonate, graphite, steel, and felt, with each new material valued for the unique tone it produces.