The resinous heartwood of Aquilaria trees, found across South and Southeast Asia. When infected by a particular mould, the wood produces a deep, complex, slightly smoky resin — agarwood, or oud. Burned on a small charcoal brazier, the smoke perfumes clothes, rooms, and people in a way that lasts for hours. One of the most expensive raw materials on earth. The smell of it in a hotel lobby signals money and tradition simultaneously.