[Hyde]

Hi,
I am really don't know much about chemistry. Which is why I am asking the experts here.
Something interesting happened and I would like to know why.
I have a bottle of tee tree oil and I finished the last drops of it only to discover that a small crystal grew inside the bottle.
Now my question, is this possible?
Or is this tee tree oil no tee tree oil but something else?
I am looking forward to your opinions and knowledge.
Thanks.

[Borek]

Tee tree oil is not a single substances, it is a mixture of many things, mostly liquid terpenes (which work as a solvent) and some smaller amounts of other, dissolved substances (this general description can be applied to many natural "oils", it is is no way specific to the tee tree oil itself). These dissolved substances can crystallize out for many reasons (including, but not limited to changes in temperature and evaporation of the solvent), that's just what happens to such mixtures.

In general: nothing unusual, even if I have no idea about what the particular substance is. Most likely nice example of natural processes taking place in natural products.

Probably people working in the related industry (I don't think any of the regulars belongs to that category) will know more details, there are some fineprints that I intentionally left out.

[Hyde]

Thank you, Borek.
That already helps a lot. I never ever have experienced this kind of crystallization in essential oils and was wondering. I do have to add though that this bottle was quite old, so it had enough time to create this crystal.
Thanks again for your answer 🙏