A heartwood from the Swartzia family of trees. Katalox grows in Southern Mexico, Central America, and northen South America. Its color can range from dark brown to black with additional reddish or purple tints. The grain is generally straight, with fine texture, though curly types are sometimes found. It is a very dense and durable wood. In musical instruments, it is used in the same applications as rosewood, ebony, wenge, and cocobolo.