Agarwood is formed in the heartwood of aquilaria trees when they become infected with a type of mould. Prior to infection, the heartwood is odourless, relatively light and pale coloured; however, as the infection progresses, the tree produces a dark aromatic resin, called aloes or agar, in response to the attack, which results in a very dense, dark, resin embedded heartwood. On this lot, lines of oud oil can be seen, releasing strong fragrance. Fusen agarwood is undoubtedly of the best quality among agarwood from all districts with its deep sweet fragrance.