Mpingo: the Timber
Mpingo is renowned for its beautiful dark coloured heartwood which in the best timber is inky black, but ranges from dark brown to even an indigo-purple tint. It is considered to be the "finest of all turnery timbers, cutting most exactly and finishing to a brilliantly polished lustrous surface". The best quality timber can fetch up to $20,000 per cubic metre, twice the price of mahogany and teak. The wood is also incredibly hard and durable. So hard, in fact, that it blunts axes, and as a result the tree is seldom cut for firewood and is sometimes left standing in fields. It is difficult to saw or plane and cannot be screwed or nailed without first drilling.
Several factors are thought to affect the colour of the heartwood. Trees growing in close proximity to the sea often have much paler brown heartwood, which means that growth rings are visible. Brown coloured heartwood is confusingly sometimes known as "white mpingo". The darkest timber is thought to be produced when the tree is growing particularly slowly. Mpingo users have found that often the timber is darker towards the outside of the trunk.
The heartwood is surrounded by a layer of cream coloured sapwood about 2cm thick, hence one of its many names: zebrawood. The sapwood is less dense than the heartwood, which can be as dense as 1.3g per cubic centimetre and sinks in water. The sapwood is significantly less resistant to termite and fungal damage. In comparison, the heartwood is resistant to biotic and abiotic agents of decay, although one species of boring beetle is known to attack it. After the tree has died the heartwood remains standing for many years.
Another name for Mpingo
Because of its dark heartwood, mpingo is frequently referred to as ebony, and mpingo is thought to be the original ebony used by the ancient Egyptians. However this is something of a misnomer; mpingo has little relationship with the true ebonies of the Ebenaceae family, and instead belongs to the rosewood genus, Dalbergia, in the pea family.