Spikenard is nice, it's unique. My little boy and I tested the theory that it attracts cats, just the other day. I can confirm that it does attract cats, which is weird, especially as it has egyptian heritage. I'd use it lightly and it's a little on the thicker and brown side than most essential oils. It would dissolve in +65% alcohol, any less and it will not dissolve. It needs 4 parts Polysorbate 20 to 1 part Spikenard to dissolve in water. So it takes some strength.
I'd suggest getting a 10ml bottle. Here's a link: http://www.idaromatics.co.uk/product...l%20Oils%20M-Z
not sure where you are based, this is UK.