Frankincense is a resin that drips down the side of four different species of Boswellia, a small tree found in India, Arabia, and Africa. The resin hardens into translucent pearls, which can be converted into an absolute by extracting with a hydrocarbon solvent, but most of the time, frankincense (sometimes called olibanum) is distilled to produce an essential oil.
Most of us are familiar with burnt frankincense, the kind encountered in a Catholic church, but when frankincense is distilled, it has a different aroma profile than when it is burnt. The smell, I hate to say, reminds me of lemon furniture polish. Achieving the aroma of burnt frankincense is something else entirely and depends on other aroma chemicals or an actual tincture of the smoke.
When I first decided to experiment with frankincense, I ordered the essential oil—the distillate—from as many sources throughout the world as I could find. After accumulating about 20 samples, I determined that they all had this similar problem—the furniture polish thing—except one. This exception—I ordered it from a wholesaler in Singapore–was purely balsamic with none of the terpenic lemony aroma. I have never smelled a substance like it, before or since, a substance more balsamic than anything I have ever experienced. When I ordered more, they had moved on to a new batch and the balsamic odor was much diminished. It was a one-time find. Unfortunately, I’ve used it all (thinking I could just order more) except for a small bottle I show to friends and curious visitors.
Usually, Frankincense is used as the essential oil, especially helpful in colognes in combination with bergamot and orange, and as a fixative in all manner of perfumes.
Frankincense is also sometimes used as a resinoid, made by extracting the residue leftover from distillation. The resinoid doesn’t have much aroma, which makes it useful as a powerful fixative.