The Prong-Set Ball with Black Onyx piece is a popular decorative end that features a 3mm Onyx stone held by 3 prongs. Onyx is opaque, meaning no light shines through it. This threadless decorative end is available in 14 karat Yellow Gold, White Gold and Rose Gold options. Measuring 3.6mm, it can be used in any piercing that is fit with a threadless post from all major jewelry vendors.