Purpleheart (Peltogyne) is a genus of 23 species of flowering plants in the family Fabaceae, native to tropical regions of Central and South America, where they occur in tropical rainforests.

The trees are prized for their beautiful heartwood which, when cut, quickly turns from a dark brown to a rich purple color. Exposure to ultraviolet (UV) light darkens the wood to a brown color with a slight hue of the original purple. This effect can be minimized with a finish containing a UV inhibitor. The dry wood is very hard and dense with a specific gravity of 0.86 (54 lb/ft^3 or 860 kg/m^3). This wood is quite dense, and if it is to be worked, then a sharp carbide blade is required to cut it. For uses of this wood it is prized for fine inlay work, woodturning, cabinetry, flooring, and furniture.

The wood is also known as amaranth and violet wood.

from  http://en.wikipedia.org/wiki/Purpleheart