What type of piercings are used for belly piercings?

Do they pierce with stainless steel to begin with? Ive had my bellybutton pierced twice, and it got infected both times. Im guessing that maybe im allergic to stainless steel piercings? But im not sure if thats the type that was used when i had it done.. Im getting it pierced again next week, and im trying to decide if i should just go with silver maybe, to reduce the risk of infection?