Oud shops are abundant here in Jeddah. Oud is a popular type of perfume sold here in Saudi Arabia that is derived from agarwood (also known as eaglewood, gharuwood, or aloeswood), which comes from the aquilaria tree. There are 17 species of the aquilaria tree, which is native to southeast Asia. The wood of tree is normally light colored, but when the tree becomes infected with mold in its heartwood, that wood turns dark with an aromatic resin that is both precious and rare. This aromatic heartwood is then turned into perfumes and incense and is highly valued in the Middle East. One reason for this could be that agarwood is highly regarded in Islam.
Many factors can affect the scent of agarwood - the species of the aquilaria tree, the geographic location where it is grown, the source from which its branch, trunk and root are derived, the length of time the heartwood was infected before harvest, as well as the methods used in harvesting and processing. The aquilaria tree is listed on the endangered species list of wild flora and fauna. Due to its rarity, it is one of the most expensive commodities in the world. Some types of oud are more expensive than even gold.