This is how to know if your lavender oil is pure and of good quality.
1. Put a drop on a white sheet of paper and wait for it to evaporate completely. There should be no stain. You should not be able to see where you put the drop once it evaporates. If you see a stain, the lavender has been stretched with another oil such as mineral oil, almond oil etc.
2. Smell the lavender. If it smells more musky or grassy than floral, you probably have lavandin, or it’s a bad quality. Sometimes the lavender is just badly distilled. The French have a long history of distilling lavender and often do a better job at distillation. The highest grades of lavender oil are very floral and can be used as perfumes! The higher the floral scent the better it can be used therapeutically for relaxation and skin care.
3. The price of the lavender oil is definitely an indication of it’s quality. If you find cheap lavender oil, you’re probably not getting the best and it’s probably not pure.