I saw this interesting video performed by Susan Parker, she demonstrated the difference between lipid carrier oils and essential oils by putting the fixed oils and essential oils in a piece of paper.
I think it is very easy way to explain it to the public regarding the differences between fixed oils and essential oils. The following is my experiences to show the differences.
I use two differences kind of fixed oils and essential oils on this experiment.
The first experiment, I used hazelnut oil vs lavender essential oil.
The second experiment, I used grape seed oil vs patchouli essential oil.
After 2 to 3 hours, the experiment shown as follows:
Comparing the two experiment, the lavender essential oil evaporate very fast within 2 – 3 hours after I applied it on the paper and it does not leave any mark stain on it. Comparison, you still can see some mark stain on Patchouli essential oil paper.
After three days, the following picture shown as follows:
The fixed oils leave permanent stain mark on the paper, and it also transparent the paper which you can see through the book at the bottom. Comparison, you did not see any stain mark leave by Lavender and Patchouli essential oils. Actually if you look closer, you can observe the very light colour stain leave on the Patchouli essential oil.
As summary, fixed oil is non-volatile and it do not evaporate compare to essential oil. Essential oil is volatile oil and it do not leave an oily mark on the paper, although any colour present will be stain.
Susan M. Parker, 2018, Carrier Oils vs. Essential Oils, https://susanmparker.com/carrier-oils-vs-essential-oils/
Price, L. & Price, S., 2008, Carrier Oils for Aromatherapy and Massage, 4th edn, Riverhead publishing.