Oh, my goodness! Thank you for asking this question, and good job for wanted only the best quality sandalwood.
Sandalwood, as we know is expensive and becoming more precious the more over-harvested it gets. Because of this, many companies who buy Sandalwood (as well as Frankincense and others) don't know that there supplier is adding synthetic fragrances (or gasoline in some cases) to. David Crow, founder of Floracopeia, personally goes to villages where sandalwood and frankincense are harvested to ensure that he is getting his oils directly from the producers. He has given many of these villages the equipment they need, cutting out the middle man. Then, we try to get the word out so that these people can continue to get the support that they need for sustainably harvesting these precious trees. Last year, they got some old growth sri lankan sandalwood from roots that were carelessly left in the ground over 40 years ago when the forest was cut. I am not sure if they have any of that left, and if they do then you should get some!
http://www.floracopeia.com/store/products/Sandalwood-Oil-(Sri-Lanka;-Organic)-dram-(3.75-ml).html
I, obviously, only get endangered oils from Floracopeia, and their non-endangered oils are incredible too.
They also have attars. Right now, they are also hosting a course on Natural Perfumery. It's pretty amazing.
This is exactly what I am doing on these forum, is looking for questions like this. Thank you.