This is from a site where essential oils are sold. The site owner is describing how this plant extract is used for insense. -- Alchemy Works

Labdanum - Cistus ladanifer, Rock Rose  This resin comes from an evergreen shrub that grows in Spain and is harvested with a leather rake.  It is much waxier than most resins, so it never completely solidifies but instead remains a very sticky, tarry substance (which is why I have put it up in little brown jars).  Also called Incense of the Black Sun, it corresponds to onycha in various recipes.  It is sometimes referred to as Black Opium, perhaps because it looks a lot like opium when it is dried.  It makes a good fixative for perfumes with a woodsy or "masculine" scent and is considered a good replacement for animal-obtained musk.  This is my favorite resin; I keep some by my reading chair and at my desk.  Its soothing scent is warm but not hot, flowery but not too sweet, sedating and uplifting mood at the same time. Concentrated, a little goes a long way, and it keeps its scent a long time, too. It is associated with Sun, Moon, Venus, Mars, Jupiter, Neptune, Scorpio, Cancer, and The Chariot, but to my mind, the best fit is Sun. This is truly a glorious smell!

*** "Very sticky, tarry substance..."
And probably added to help ease the stinky smell of burning tobacco and other chemicals.
Please also note the warning label on the bottle above: Keep away from eyes.. children! ***

Warning: Avoid during pregnancy. -- Alexander Essentials