The Tree
The average height is 30m with a diameter up to 1.0m; the bole length, above the arched, plank buttresses is usually no more than 20m. The bole is cylindrical and well formed when the trees grow on well-drained sites, but in swampy areas it is twisted and irregular.

The Timber
The heartwood and sapwood are not clearly distinct. The heartwood varies from pale pink to reddish-brown; the sapwood is lighter coloured and about 75mm wide. The gain is often wavy and interlocked, so that quarter-sawn material shows an irregular stripe figure. The texture is rather coarse, and the timber has a greasy feel, due to the presence of resin. The weight is variable from 512 to 770 kg/m3, and averaging about 625 kg/m3 when dried Niangon is similar to African mahogany but coarser in texture and denser. The two timbers may also be distinguished by examination of the radial surface (quarter-sawn) in niangon the large rays are conspicuous as dark flecks; in mahogany they are hardly visible. This characteristic gives niangon an attractive figure when quarter-sawn, which is often emphasised by the interlocking grain.

Drying
The timber presents only minor drying problems, and it dries fairly rapidly. A small proportion of the wood may show a tendency to twist. There might be slight end splitting and surface checking and very slight collapse may occur in a few boards.

Strength
Similar to African mahogany, but in compression, hardness, and resistance to shear and splitting, is appreciably superior and almost equal to oak.

Working Qualities
Good - Fairly easy to work. It does not dull cutting edges to any appreciable extent. A considerable improvement in finish is gained by reducing cutting angles to 150. The timber stains and polishes well but requires a rather large amount of filler; excess of gum in the wood may sometimes create difficulties in finishing. Takes nails and screws satisfactorily, and generally glues quite well, though the French recommend a preliminary treatment with a solution of caustic soda or ammonia to overcome the resinous nature of the wood prior to gluing or varnishing.