Rose oil the aromatics unaltered by heat. Because CO is gas at normal atmospheric pressure, it leaves no trace of itself in the final product. The equipment for CO extraction is expensive, which is reflected in the price of the essential oils obtained from the process. It takes a large amount of rose petals to distill a small amount of essential oil. Depending on extraction method and plant species, the typical yield can be approximately 1:3,000. To mitigate the cost, some dishonest dealers will dilute rose oil with geranium ("Pelargonium graveolens") or palmarosa ("Cymbopogon martinii") essential oils, both of which are rich
Bergamot essential oil and furanocoumarins. The main compounds in the oil are limonene, linalyl acetate, linalool, γ-terpinene and β-pinene, and in smaller quantities geranial and β-bisabolene. The main non-volatile compounds are coumarins (citropten, 5-geranyloxy-7-methoxycoumarin) and furanocoumarins (bergapten, bergamottin). The bergamot essential oil is particularly subject to adulteration being an essential oil produced in relatively small quantities. Generally adulteration is to "cut" the oil, i.e. adding distilled essences of poor quality and low cost, for example of bitter orange and bergamot mint and/or mixtures of terpenes, natural or synthetic, or "reconstruct" the essence from synthetic chemicals, coloring it with chlorophyll. Worldwide, each year, around