Ebony is a medium-sized evergreen tree in the genus Diospyros, and is native to southern India and Sri Lanka. It is noted for its heavy black, fine-grained heartwood. Ebony heartwood is one of the most intensely black woods known. Combined with its exceptionally high density (it is one of only a few woods that sink in water), fine texture, and ability to polish very smoothly, it is valuable as both an ornamental and functional wood. This makes it an extremely good choice for fingerboards. Ebony tree forests that once covered large areas have shrunken significantly due to rapid urbanization. Today, as a result of unsustainable harvesting, many species of ebony are now considered threatened or even endangered. This makes ebony difficult to obtain for use on musical instruments, much like Brazilian rosewood.