14K White Gold Ruby Stud Earrings Ruby, in a simple and classic setting, is the centerpiece of these lovely earrings. The tiffany style stud earrings contain two created 5mm round red ruby gemstones and are crafted of cool, gleaming 14K solid white gold. The ruby stud earrings contain 14K white gold post backings for a secure, comfortable fit. Ruby is the birthstone for July.