Frankincense is a gum resin obtained from the Boswellia tree. The resin is harvested in rounded irregularly-shaped tears, which are usually coated in a whitish substance caused by the pieces rubbing together. When burned, frankincense produces a complex fragrance, at once sweet, fruity and woody. It has long been used as an ingredient in perfumery and aromatherapy.
Frankincense was an important commodity in ancient times. In the New Testament story of the Nativity, frankincense was one of the gifts borne by the three wise men. The ancient Egyptians used frankincense as a natural insecticide, and also as an ingredient in their embalming method. Frankincense was recommended as medicine by the Arabian physician Avicenna in the 11th century, used by Greek and Roman physicians and mentioned in both Chinese and Ayurvedic medical texts. It served as a part of ancient Jewish religious ritual and later was burned as part of the Roman Catholic mass.
There are different species of the Boswellia tree, but all require an arid climate. Boswellia trees grow primarily in the southern Arabian countries of Oman and Yemen, India, and parts of northern Africa, including Somalia, Ethiopia, Eritrea and Kenya. Boswellia trees are relatively small (20 feet in height) and scrubby. They prefer soil rich in limestone and often grow in dry riverbeds or on cliffs and rocky hillsides, making harvesting of the resin difficult.
Frankincense resin is created when the boswellia tree is injured. The sticky white liquid produced by the tree to heal its wound is in Arabic called "luban," meaning white or cream. Workers use a tool called a mengaff to scrape 5-inch sections of the tree's bark away to initiate the resin's release. After the resin hardens, it is collected, then sent to market. According to the Scents of Earth website, the trees which produce the resin are best harvested twice annually, from January to March and again from August to October. Giving the tree time to rest allows it to produce better quality resin.
The hardened pieces of frankincense gum, or tears, are generally divided into four grades, according to Floracopedia.com. The highest grade, or superfine, is a translucent pale yellow, and contains no impurities. The next highest grade is first quality, which is less translucent and darker yellow, but still has no impurities or bark. Beneath this grade is second quality, a semi-translucent brown with some impurities. The lowest grade is third quality, which is an opaque dark brown with impurities.
Preliminary studies involving frankincense have suggested that it can potentially decrease inflammation, according to WebMD. Boswellia serrata, an Indian species most commonly used for medical uses, has been suggested as a treatment for joint pain caused by rheumatoid arthritis, osteoarthritis, rheumatism, bursitis and tendonitis. Frankincense has also been used to treat abdominal pain, ulcerative colitis, asthma, hayfever, painful menstruation and cancer, although more evidence is required to prove its efficacy.