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Agarwood is from trees of the genus aqualaria that grow mainly from
northeast India down into southeast Asia. The wood is heavy, dark and hard.
When the tree is infected by a group of fungi it creates a resinous oil
(apparently to defend against this fungi) which has a deep, dark, rich,
beautiful, woody aroma. The wood is used as an incense for both pleasure
and spiritual enhancement. The essential oil distilled from this wood
(known as Oud in Arabic) is used for the same reasons as well as a perfume
and medicine. The oil is mentioned in the Bible as Aloes. Agarwood is one
of the most expensive and problematic sources of essential oil in the world.
This incredibly beautiful wood is also used in the Japanese incense