What gauge headpin fits a 3mm swarovski crystal?

I’m new to this and want to order 3mm faceted bicone swarovski crystal beads and need to know the gauge i should order so the headpin will fit the whole, i dont want it to not fit or be way to small, please help
I’m planning on making earrings to sell, I haven’t started ter obviously, so i’ll be experimenting when I get my stuff, thank you for the info!!! I was having the hardest time trying to figure out what to order

24 gauge works well for that size Swar crystal
Try http://www.firemountaingems.com/shopping.asp?skw=KWFNHEADPINSS for looking at different sizes in Sterling silver, which show you the actual size of the body of the headpin.
Hmmm, what are you making??

Crystal Facet Beads
Crystal Facet Beads
Crystal Facet Beads