Sourcing and purchasing organic essential oils from countries around the world is not a job for a novice or the faint-hearted, because mistakes can be very, very costly. It takes many years of training to learn about the differences in therapeutic properties and also the organic chemistry between a given species. Take a random selection of any essential oils produced from the same botanical species and they will undoubtedly differ in quality, for any number of reasons. 

These variations can be due to blatant adulteration with synthetic or isolated chemicals, and this can account for a large amount of poor quality essential oils. Sometimes essential oils are diluted with vegetable oils but not labelled as such, making them very poor value for money. But these typical instances do not account for everything when evaluating the quality of an essential oil.  

The fertility of the soil the plant was grown in, the prevailing climate, the time of the harvest and level of expertise used in the process of extraction will all have a significant effect on the final quality of an essential oil. This is why the country of origin is so important when it comes to the quality of an oil, since the climatic and soil conditions greatly affect the oil producing cells within the plant.