Olibanum

#### Olibanum. Olibanum is a natural oleo-gum-resin. It is formed as a physiological liquid product in the bark of various **Boswellia **species. These are small trees originating in the mountainous areas of western India, southern Arabia and northeastern Africa. The trees are not cultivated, and collection of the olibanum is made where the trees are most abundant, i.e. Somaliland and Somalia, rarely in south Arabia (near the limestone mountains of Fartak). At least four different species of **Boswellia **are recognized as parent plants of the commercial Olibanum. To increase the production of olibanum from the bark, the natives (mostly Bedouins) make incisions in the bark at regular intervals. The viscous oleo-gum-resin which oozes out will soon resinify, and is either broken off the branches or collected from the ground where it sometimes may fall. The collected material is sorted and graded locally or at the port of departure (Djibouti, Aden, Mogadiscio, Berbera, etc.). The grading is primarily an "appearance" grading, and the author strongly disagrees with published statements, such as, "— — dust and siftings: because of its low price, the most suitable for distillation". When resinous material is being evaluated, it is of paramount importance to remember that the larger the surface, the more complete the resinification, and, consequently, the higher the loss of volatile matter, e. g. essential oil. Usually the dust and siftings give a comparatively low yield of essential oil of a very poor odor (from a perfumery point of view). Furthermore, there is no straight rule as to which color of olibanum "tears" or "lumps" will yield the best oil. The odor of the crude botanical will give certain indications; an experimental distillation will give the best answer. Experience in selecting the correct material for distillation or for the extraction of resinoids or absolutes, is a rare and valuable skill, and is partly based upon years of experimenting with the distillation and extraction of all grades of olibanum. **Olibanum **appears as pale yellow or pale amber- colored, tear-shaped or drop-shaped, egg-shaped or almost round lumps, varying from pea-sized to walnut-size. Other grades may be orange- yellow, orange-red or brownish in color, and the tears may be agglutinated into large lumps. For odor and composition, see the monographs: **Olibanum Absolute **(so-called), **Olibanum Oil**, and **Olibanum Resinoid**.