.925 sterling silver Gemstone(s): Swiss Blue Topaz = approximately 0.90 ct. tw. Pendant drops approximately 0.2in Approximately 18in long Spring ring clasp closure 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.