You will find these oils to be of the highest quality. As in the perfume industry, the trade reference for an unblended essential oil is called a single note . When blended together with other oils, we refer to this as a synergy or multi-note. We also use the term high note, middle note and base note to refer to the intensity of the oil. High notes are the first thing you smell when you open a bottle of essential oil, fragrance oil, perfume oil, etc., but they dissipate quickest.
Middle notes stabilize the blend and last longer than the high notes.
Base notes are the most lingering, this is the one you smell after you've had perfume on all day. Each oil contains different constituants or characteristics which make it different from the rest. Essential oils are highly concentrated substances and as such should be treated with respect. Never take oils internally. Keep undiluted oils stored in glass bottles.