Commiphera myrrha or true myrrh occurs in Somalia and the Arabian peninsula, along with about eight other species which are often mixed together in commercially available crude resin. The trunks of both frankincense and myrrh trees exude a sticky substance called oleo gum resin. The crude resin of frankincense and myrrh can be treated in one of two ways to produce liquid aromatics. The resin is soluble in chemical solvents and the essential oil can be steam distilled. The solvent extraction process produces a viscous, almost solid substance called a resinoid.
Resinoids are soluble in high-grade, odorless alcohols.
Alcohol dissolved resinoids are sometimes passed off as distilled essential oils. Resinoids are often used in perfume making. Steam distilled essential oils of frankincense and myrrh are most appropriate for use in aromatherapy. Oil of frankincense is slightly viscous, yellow to green with a deeply balsamic, fresh-resinous aroma. Oil of myrrh is slightly viscous, yellowish to amber orange with a warm-spicy, balsamic fragrance.