Natural Sphalerite 16.28 caratSphalerite natural sphalerite gemstone. Sphalerite is a mineral that can come in various shapes and colors, often used in jewelry when cut and polished. An 16. 28 carat octagon shaped sphalerite would likely make for a stunning and unique piece Natural sphalerite, with its captivating luster and rich colors, is a gemstone prized by collectors and enthusiasts alike. Formed from zinc and often found alongside other minerals, sphalerite showcases a