Aromatic: This is the most defining feature, as they possess a distinctive, often strong, fragrance.
Volatile: They evaporate quickly at room temperature, leaving little or no residue.
Non-greasy: Unlike fatty oils, they do not feel greasy or oily on the skin.
Lipophilic: They dissolve readily in fats and oils, but not in water.
Color: Can vary widely depending on the plant source, ranging from clear and colorless to deep amber or even green.
Density: Typically denser than water, meaning they sink in water.
Viscosity: Can vary from thin and runny to thick and syrupy.
Flammability: Many essential oils are flammable, especially when exposed to heat or flame.
Optical Activity: Some essential oils exhibit optical activity, meaning they rotate the plane of polarized light.
Chemical Composition: This is the basis for the oil's unique properties. Essential oils consist of various volatile compounds, including:
* Terpenes: Often responsible for the fragrance.
* Esters: Contribute to floral or fruity scents.
* Aldehydes: Can be pungent or spicy.
* Ketones: Contribute to camphoraceous or minty scents.
* Alcohols: Contribute to fresh or herbaceous scents.
* Phenols: Can have antiseptic properties.
Here's an important note: While these characteristics are generally true for essential oils, there can be variations within different types. For example, some oils are thicker or lighter in color than others.
It is crucial to remember that essential oils are concentrated and should always be used with caution. Dilution with carrier oils and proper storage are essential for safe and effective use.
