Sadly, most EOs are adulterated with various synthetic and natural components to both bring the price to a level the market will bear and to improve a poor oil so it can be sold. Most people will not know the difference between an EO that's been altered and stretched and one that hasn't. The suppliers of very high quality oils are enormously expensive, yet that reflects the true cost of an essential oil. Usually a lot more than the average consumer is willing to pay.
France exports more Lavender oil than it actually produces. That's because it's EO is being stretched and improved with synthetic components and other cheaper oils that are only detectable by an expert and gas chromatography. It's estimated that 90% of all essential oils sold are actually a melange of synthetic components and an essential oil, often altered at source before the distributors and retailers even see them. It's for this reason I don't fragrance my soap as even the more common EOs aren't what we think they are. :cry:
I do purchase high quality EOs for perfumery and even the price of a simple lavender will surprise you. These are oils that the retailer sources directly from a traditional distiller. The distillery gets a higher price for their product and an incentive to maintain it's quality, rather than having their products auctioned off to market dominators who's main objective is to sell a lot of oil at a lower price point. One has to wonder what a realistic price is for a substance that is difficult and costly to produce and consumes vast amounts of plant material in it's manufacture. Most essential oils of undiluted quality are too expensive to buy in sizes larger than a 1/2 Oz.
Sometimes this extending is as simple as mixing a higher quality EO with a cheaper but similar smelling EO of another plant. That does change the scent profile somewhat which is then rectified by adding the notes which are now 'off' synthetically. Rosemary oil is routinely extended with eucalyptus, they smell similar in the top note but the drydown is different. Ever bought a rosemary EO that you thought for sure was eucalyptus? Now you know why. Other times a poorly produced oil, lets say lemon is recitified by having synthetic citral added to it, to make it more lemony and what the consumer expects. Therefore more marketable.
The reality is that we are now so accustomed to synthetic versions of scents that we do not have an acute understanding of what the real thing smells like. Coconut is a really good example of this. That scent we all recognise as coconut doesn't smell much like natural coconut odour which I find to be quite nauseating. We've been conditioned to a version of it which has copious amounts of coumarin added in order to make it more palatable to people. I've never come across an apple that smells anything like synthetic apple fragrance which has been constructed to trigger our brain receptors to think 'apple' when we smell it. I'm actually really fascinated with the overt conditioning of our sense of smell by cosmetic and food manufacturers. The brain can be tricked easily with certain chemicals, some of them have no odour in and of themselves but they trigger a certain memory response in the brain so that we think we are smelling a certain thing.