Is jojoba oil 100% pure?

I am using jojoba oil for my hair since a year and the results were really great. My hair now looks more shinny and vibrant. But the thing which has started bothering me is whether jojoba oil is 100% pure. As till now I have not faced any problem. I want to know that if I keep using it, will it cause any harm to my scalp. Any help will be great.