Frankincense (also known as olibanum, Persian: کندر [Kondoor], Hebrew: לבונה [levoˈna], Arabic: اللبان al-libān or Arabic: البخور al-bakhūr, Somali: Uunsi) is an aromatic resin used in incense and perfumes, obtained from trees of the genus Boswellia in the family Burseraceae, particularly Boswellia sacra (syn. B. bhaw-dajiana), B. carterii, B. frereana, B. serrata (B. thurifera, Indian frankincense), and B. papyrifera. The word is from Old French franc encens ('high-quality incense').
There are five main species of Boswellia that produce true frankincense. Resin from each of the five is available in various grades, which depend on the time of harvesting. The resin is hand-sorted for quality.
A popular folk etymology suggests a connection with the Franks (and often in particular Frankish Crusaders), who reintroduced the spice to Western Europe from their trade with the Byzantine Empire during the Middle Ages, but the word itself comes from the expression.
In Koine Greek (the language of the New Testament), Arabic, Phoenician and Hebrew, the name of frankincense is cognate with the name of Lebanon; this is postulated to be because they both derive from the word for "white" and that the spice route went via Mount Lebanon.
The trees start producing resin at about eight to 10 years old. Tapping is done two to three times a year with the final taps producing the best tears due to their higher aromatic terpene, sesquiterpene and diterpene content. Generally speaking, the more opaque resins are the best quality. Fine resin is produced in Somaliland, from which the Roman Catholic Church purchases most of its stock.
Recent studies indicate that frankincense tree populations are declining, partly due to over-exploitation. Heavily tapped trees produce seeds that germinate at only 16% while seeds of trees that had not been tapped germinate at more than 80%. In addition, burning, grazing, and attacks by the longhorn beetle have reduced the tree population. Conversion (clearing) of frankincense woodlands to agriculture is also a major threat.
Frankincense was reintroduced to Western Europe by Frankish Crusaders, and other Western Europeans on their journeys to the Eastern Roman Empire where it was commonly used in church services. Although named Frankincense, the name refers to the quality of incense brought to Western Europe, not to the Franks themselves.
The Greek historian Herodotus was familiar with frankincense and knew it was harvested from trees in Southern Arabia. He reported that the gum was dangerous to harvest because of venomous snakes that lived in the trees. He goes on to describe the method used by the Arabs to get around this problem, that being the burning of the gum of the styrax tree whose smoke would drive the snakes away.
Southern Arabia was a major exporter of frankincense in antiquity, with some of it being traded as far as China. The 13th-century Chinese writer and customs inspector Zhao Rugua wrote on the origin of frankincense, and of its being traded to China:
"Ruxiang or xunluxiang comes from the three Dashi [Arab] countries of Murbat (Maloba), Shihr (Shihe), and Dhofar (Nufa), from the depths of the remotest mountains. The tree which yields this drug may generally be compared to the pine tree. Its trunk is notched with a hatchet, upon which the resin flows out, and, when hardened, turns into incense, which is gathered and made into lumps. It is transported on elephants to the Dashi (on the coast), who then load it upon their ships to exchange it for other commodities in Sanfoqi. This is the reason why it is commonly collected at and known as a product of Sanfoqi."
Thousands of tons of frankincense are traded every year to be used in religious ceremonies as incense in thuribles and by makers of perfumes, natural medicines, and essential oils. It can be inhaled or applied to the skin for its supposed health benefits. Most frankincense comes from Somaliland, Somalia and India, but also in Oman, Yemen, and western Africa.
In Somaliland and Somalia, frankincense is harvested in the Bari and Sanaag regions: mountains lying at the northwest of Erigavo; El Afweyn District; Cal Madow mountain range, a westerly escarpment that runs parallel to the coast; Cal Miskeed, including Hantaara and Habeeno plateau and a middle segment of the frankincense-growing escarpment; Karkaar mountains or eastern escarpment, which lies at the eastern fringe of the frankinscence escarpment.
In Dhofar, Oman, frankincense species grow north of Salalah and were traded in the ancient coastal city of Sumhuram, now Khor Rori.
In 1998, the International Union for Conservation of Nature (IUCN) warned that one of the primary frankincense species, Boswellia sacra, is "near threatened". Frankincense trees are not covered by the , but experts argue that Boswellia species meet the criteria for protection. In a 2006 study, an ecologist at Wageningen University & Research claimed that, by the late-1990s, Boswellia papyrifera trees in Eritrea were becoming hard to find. In 2019, a new paper predicted a 50% reduction in Boswellia papyrifera within the next two decades. This species, found mainly in Ethiopia, Eritrea, and Sudan, accounts for about two-thirds of global frankincense production. The paper warns that all Boswellia species are threatened by habitat loss and overexploitation. Most Boswellia grow in harsh, arid regions beset by poverty and conflict. Harvesting and selling the tree's resin is one of the only sources of income for the inhabitants, resulting in overtapping.
In Chinese medicine, it (ru xiang) along with myrrh (mo yao) have anti-bacterial properties as well as blood-moving uses. It can be used topically or orally. The Egyptians cleansed body cavities in the mummification process with frankincense and natron. In Persian medicine, it is used for diabetes, gastritis and stomach ulcer.
The incense offering occupied a prominent position in the sacrificial legislation of the ancient Hebrews. The Book of Exodus (30:34-38) prescribes frankincense, blended with equal amounts of three aromatic spices, to be ground and burnt in the sacred altar before the Ark of the Covenant in the wilderness Tabernacle, where it was meant to be a holy offering—not to be enjoyed for its fragrance. Scholars have identified frankincense as what the Book of Jeremiah (6:20) relates was imported from Sheba during the 6th century BC Babylonian captivity.
The essential oil of frankincense is produced by steam distillation of the tree resin. The oil's chemical components are 75% monoterpenes, sesquiterpenes, monoterpenoles, sesquiterpenols and ketones. Contrary to some commercial claims, steam distilled frankincense oils do not contain the insufficiently volatile boswellic acids (triterpenoids), although they may be present in solvent extractions. The chemistry of the essential oil is mainly monoterpenes and sesquiterpenes, such as alpha-pinene, Limonene, alpha-Thujene, and beta-Pinene with small amounts of diterpenoid components being the upper limit in terms of molecular weight.