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
Essential oil purity, and sometimes related to the toxicity of specific chemical components of the oil. Many essential oils are designed exclusively for their aroma-therapeutic quality; these essential oils generally should not be applied directly to the skin in their undiluted or "neat" form. Some can cause severe irritation, provoke an allergic reaction and, over time, prove hepatotoxic. Some essential oils, including many of the citrus peel oils, are photosensitizers, increasing the skin's vulnerability to sunlight. Industrial users of essential oils should consult the safety data sheets (SDS) to determine the hazards and handling requirements of particular oils. Even certain therapeutic grade