Oak moss Absolute,(Evernia prunastri and furfuracea) is a tree moss used as a fixative base note in perfumery. A fixative holds the blend together and allows the aroma to unfold in layers of transformational scent. A natural perfume is always about transforming and uplifting energy to its highest form. Diluted in a perfume, Oak moss is very calming. Oak moss has low volatility and evaporates slowly without affecting the evaporation of other essential oils in a blend. It blends well with many other essences, used in small amounts, and other fixatives, such as Benzoin, Labdanum, Vetiver, Patchouli, Tarragon and Lavender Concrete.