This Children's 5 MM Round Blue Topaz Post Stud Earrings is 14K Yellow Gold. Sky Blue Topaz stone type. Length is 5 MM. Width is 5 MM. Earring closure is post and push back. Caring for Your Gold Jewelry: to keep gold shining and scratch-free, avoid contact with chlorine and other harsh chemicals. Do not wear jewelry during rough work and be sure to store it in a fabric jewelry box or pouch. To clean gold jewelry, use warm water, a mild soap, and a soft-bristled brush, if needed.