I know they're soft stones, so do they have to be set into gold or platinum or can studs and solitare pendants be setting into sterling silver?
Sterling is probably a better choice with apatites. They are not only soft but extremely brittle, making setting them quite a nerve wracking procedure. I'd have a discussion with your jeweler about this prior to doing it, as the chances of the stone being chipped during setting are a lot higher than with most other stones. I won't touch the little devils anymore..I just can't take the stress !