The resinous heartwood of agarwood, oud, is also used to refer to the resin extracted from the material. Almost all of the ingredients labelled “agarwood” or “oud” — also another name for agarwood, or any agarwood derived products — in modern perfumery are synthetic, and not immediately derived from organic agarwood sources. Natural oud and synthetic mock versions are said to differ quite substantially, with the synthetic variants not yet able to replicate the complex aromas of the luxury item. Oud is woody in essence, yet carries subtleties of balsamic. It is also noticeably nutty and sweet.