Piano keys are generally made of spruce or basswood, for lightness.
Spruce is normally used in high-quality pianos.
Traditionally, the black keys were made from ebony and the white keys were covered with strips of ivory, but since ivory-yielding species are now endangered and protected by treaty, plastics are now almost exclusively used.
Legal ivory can still be obtained in limited quantities.
At one time, the Yamaha firm innovated a plastic called "Ivorine" or "Ivorite", since imitated by other makers, that mimics the look and feel of ivory.