I got the Black Star a while back and decided to use it today, I killed a guard, trapping his soul in the star. Then when I tried to recharge my weapon the star didn't appear in the list of possible choices.
Any idea why? This is the first soul that I have trapped in the star.
Okay so after experimentation it turns out because of the black star's name you can only have 2 other kinds of soul gems in your inventory or you wont be able to see the star. Hope this helps Anyone else with the same issue