Essential oils and Absolutes

An essential oil is a substance that has been extracted from a plant through the means of distillation (as with lavender and rosemary) or expression/cold pressing (as with the peels of citrus fruits).
An absolute is a substance that has been extracted through the process of enfleurage, which uses a solvent. In enfleurage, flower petals are layered in wax or clean animal fats. Over several days, the wax or fat becomes saturated with the oil from the petals or plant material. The process is then repeated by replacing the spent botanicals with fresh ones until the fat has reached the desired degree of fragrance saturation. The scented fat or wax fat is now called a pomade. The pomade is washed or soaked in a solvent, typically ethyl alcohol, to draw the fragrant molecules into the alcohol, creating a concrete. The alcohol is then separated from the fat or wax and allowed to evaporate. The final result is the absolute.

Absolutes differ from essential oils in that their fragrance is usually stronger and more concentrated. They are used most often by perfumers and serve as valuable oils when creating their signature scents.

ESSENTIAL OILS
Anise, Basil, Bay Laurel, Bergamot, Birch, Black Pepper, Black Spruce, Blue Tansy, Cardamom, Cedarwood, Chamomile, Cinnamon, Citronella, Clary Sage, Clove, Coriander, Cypress, Eucalyptus, Fennel, Fir, Frankincense, Galbanum, Geranium, Ginger, Grapefruit, Helichrysum, Juniper Berry, Lavender, Lemon, Lemongrass, Lime, Marjoram, Mandarin, Melissa, Myrrh, Neroli, Niaouli, Nutmeg, Orange, Oregano, Palmarosa, Palo Santo, Patchouli, Peppermint, Petitgrain, Pine, Ravensara, Ravintsara, Rosemary, Sage, Sandalwood, Spearmint, Spike Lavender, Spikenard, Spruce, Tangerine, Tea Tree, Thyme, Vetiver, Wintergreen, Ylang Ylang

ABSOLUTES
Arnica, Carnation, Honeysuckle, Jasmine, Labdanum, Marigold, Mimosa, Narcissus, Oak Moss, Opopanax, Rose, Tuberose, Vanilla, Verbena, Violet

Note: Partial list of essential oils and absolutes.