Olea capensis
Olea capensis, the black ironwood, is an African tree species in the olive family Oleaceae. It is widespread in sub-Saharan Africa: from the east in Somalia, Ethiopia and Sudan, south to the tip of South Africa, and west to Cameroon, Sierra Leone and the islands of the Gulf of Guinea, as well as Madagascar and the Comoros. It occurs in bush, littoral scrub and evergreen forest. Other common names in English include ironwood, ironwood olive, East African olive and Elgon olive. Description. The black ironwood is a bushy shrub, or a small to medium-sized tree, up  to in height, occasionally reaching . Subspecies. The species has been divided into 3 subspecies: "Olea capensis" has masses of sweetly scented bisexual flowers, that produce large edible fruits. The wood of the tree is very hard, fine grained, and heavy, and although difficult to work, it is widely used for art and artifacts. "Olea capensis" is cultivated as an ornamental tree in parks and gardens. Uses. The Guinness Book of World Records lists this tree as the world's heaviest wood, with a specific gravity of 1.49, similar to that of anthracite or dry earth. It is known for its  tendency to sink in water, unlike other wood materials. It is also the one of the world's hardest woods according to the Janka hardness test. The timber has a good abrasion resistance and is very strong. It is an excellent turnery wood, and is used for a wide range of decorative items.