The black and white keys of the piano are made of wood covered with veneer. Most pianos that were made before 1960 have white keys with thin ivory tops. The black keys are traditionally made with ebony.
The keys of old pianos are made of sugar pine wood. Newer piano keys are made of either spruce or basswood. Since the ban on the use of ivory was placed, the white key tops on modern pianos as well as the black ones are mostly made with acrylic plastic. Cellulose plastic is also used, but this material is flammable. Piano keys with cigarette burns are likely to have been made with cellulose. Glass and porcelain were once used as key tops.