18-karat yellow gold Diamond = approximately 0.75 ct. tw. Ring cannot be re-sized It is customary to treat most gemstones to achieve enhanced color and durability. Some of these treatments may not be permanent, and may require special care. Please note: In product titles ct. tw. refers to the total carat weight of all diamonds and/or gemstones combined. Our products are 100% genuine. In some cases we purchase merchandise from trusted independent suppliers and not directly from the brand owner. In all cases we stand by the authenticity of every product sold on our site.