Cabochon Opal & Diamond Earring Studs in Yellow GoldCabochon Opal Diamond Earring Studs in Yellow Gold. These modern stud earrings feature 1. 76 carats of cabochon cut opals and . 12 carats of round brilliant diamonds set in 14 karat yellow gold. The simple design makes great use of the brilliant diamonds sparkling above the creamy opals with their lovely flashes of color. These could be fabulous for daily wear and would look very at home at a fancy gala event.