Scientific name: genus: Diospyros
Ebony is extremely dense, fine-grained black wood. It does not float in water. Ebony is most famously used to make the black keys on a piano.
Mahogany is a generic name given to several different kinds of reddish-brown furniture grade timber, either from tropical regions or the Americas.
Pine is a soft, cheap timber, commonly used for making floors and furniture. It becomes more yellow as it ages.