A real classic nipple stud with two crystal on the frontside of the balls. Besides the very striking colors these nipple bars have a titanium plating. This makes them better protected against scratching and as long as they remain unscratched or damaged they an be worn by someone with a mild nickel allergy. The underlying material is surgical steel.
Front facing nipple bars are popular. Also see the related products to find silver nipple studs with front facing gemstones. For your nipple piercings you can also find circular barbells with a similar design.