The Meaning of Volatile and Essential when Applied to Essential Oils
The term "essential" means that the oils contain the fragrant part of the plant, also known as essence. Essence means spirit, and in Alchemy, spirit is the part of the substance that still possesses the original qualities. Essential oils contain hundreds of components that posses different characteristics, and they are responsible for the properties of the oils.
Volatile comes from latin and means, "to fly". Essential oils vaporize when they are exposed to air, therefore the term volatile is applied to them. The essential oils evaporate at room temperature. The components of the oils are volatile and they are very easily lifted up into the air. Each essential oil evaporates at different rate. Most of the essential oils have high Brownian movement. This means that the more heat put into the system the more they evaporate into the air. An essential oil used in a tea light evaporates more quickly than if it was dropped on an aromatherapy stone. This is because the oil is warmed in a diffuser and more energy is put into the system.