These Black Onyx Studs are made using a pair of genuine Black Onyx gemstones. They are carefully made by hand using solid Sterling Silver. They They thread through the ear like a post type earring would, but it is 1.5" long and includes a clear silicone back that you push to the back of the ear to hold earring into place. The stone measures 6mm in diameter, a simple yet exquisite pair of earrings.