Question: [Wednesday, 25th Nissan, 5781]
I often smell essential oils, such as Levona, and would like to know if a blessing of Minei Besamim should be said prior to smelling them?
Yes. Natural 100% essential oils that have a good scent are to be blessed upon prior to being smelled, as is the law regarding all spices. The exact blessing is dependent on the type of herbs the essential oil is derived from. For example, peppermint oil is Isvei Besamim, just as is the law regarding the peppermint leaf, while Levona oil would be Atzei Besamim, being that it is made from the sap of the tree. If you do not know the source of the oil but know that it is 100% herb, then simply say the blessing of Minei Besamim. If it is not 100% herb derivative and contains chemicals and artificially made smells and scents, then a blessing is not to be recited.
Sources: See Admur Seder Birchas Hanehnin 11:6; Piskeiy Teshuvos 216:8-11