Have you seen this ad? It conceals a fraud. Spike lavender for painting has a long history of adulteration with turpentine; this is first recorded in the De Mayerne Manuscript. The price of spike lavender is now such that the solvent sold to painters is not even an adulteration, but an invention. European companies are required to list the actual compounds in their “spike lavender,” but American companies are not. Spike lavender has three major components and dozens of minor ones. The three major ones are Linalol (26-44%), 1,8-Cineole (25-36%), and Camphor (5.3-14.3 %). These compounds occur in many other plants, or can be made in a laboratory. Adulteration of lavender, the most popular essential oil scent, is especially sophisticated. A recent paper noted that while 20 tons of fine lavender are refined each year in France, 250 tons are exported.
The European MSDS files I’ve examined show no actual spike lavender content. These materials are either a mixture of VOC solvents such as turpentine, pine oil, and D-limonene, with a little camphor and linalyl acetate to supply the specific smell, or a mixture of either synthetic or, at a higher price point, natural essential oils similar to the major components of actual spike lavender. The American companies claim their solvents are safer – presumably because VOCs (volatile organic compounds) are considered more toxic that FOCs (volatile floral compounds), but their “MSDS” files are meaningless because they do not list what is in the solvent. The consumer assumes that this is spike lavender, but the finest print does not confirm this, and the price point of these solvents makes this an economic impossibility.
So, American companies like Art Treehouse and Chelsea Classic Studios are selling something else, not genuine spike lavender, and no one knows what it is. Is this harmless? What is being hidden? A product containing VOC solvents or synthetic compounds made in a lab? It is impossible to know.
As of Spring, 2019, genuine spike lavender costs about 500-550 dollars per quart, or 26-28 dollars per ounce. Actual spike lavender can be purchased through an essential oil company that provides a GC/MS (gas chromatography/mass spectrometry) analysis sheet: for example, Lotus Botanicals in Maine. The compounds that make up spike are about half the same as those in genuine lavender, so actual spike smells like a more spicy or penetrating version of lavender, its odor is integrated, not fragmented.
The only technical reason to use spike lavender is to dissolve sandarac or Manila copal, not exactly everyday painting materials at this point. The essential oils of eucalyptus and rosemary also dissolve these resins, and may be easier to find in an unadulterated form.