A great everyday necklace. The Herkimer Diamond necklace is a raw crystal piece that ranges from clear to threads of grey & black in it. The different strands are what makes these gemstone inherently beautiful. +Herkimer Diamond. 14k Gold Fill Chain. Lobster Clasp. +Length: 17 inches (43.1 cm). Width of Gemstone: approx .5 inches (1.27 cm).