Add a little glimmer to your piercing. The opal captive bead ball adds gleaming color and iridescence to any captive ring. Each bead is crafted of a synthetic man made opal. The composition of the opal is 80% Si2.nH20 and 20% resin. These opal captive balls are available in 3mm, 4mm or 5mm. There are a variety of colors to choose from making appearance change easy.