In perfumery, the word incense usually, but not always, refers to frankincense. The resin of trees from the Boswellia genus has been used as incense and in perfume for over six thousand years. One of the highest grades of frankincense, prized for its purity, is harvested from the Boswellia sacra species which grows in Oman, Yemen and Somalia. Frankincense has facets of pine, citrus, developing a smoky caramel note as it burns. An indispensable component in oriental and woody compositions, Frankincense is often paired with myrrh, benzoin and other resins.