Ark Angel Alchemy 12ct. Natural Sterling Silver Amethyst Necklace 18" with Extender The necklace gemstones span 97mm with a hanging length of 10mm at the center of the necklace.. Weighing 11 grams. Necklace is 18" with a 2" extender to vary the necklace length. The total necklace length is 20".* The amethysts are top quality, with a deep, purple color. The large, teardrop stone is 12mm x 8mm and marquis gemstones are 12mm x 6mm.* Handmade, Polished Finish, Natural Gemstones, Excellent Quality, Meticulous Detail. Includes a Free, Silver Gift Box.