This is a wonderful, large Herkimer diamond quartz crystal securely locked in its forever home of dolomitic limestone. The vug the crystal rests in has a little bit of black hydrocarbon lining it, which is a wonderful background for the clear quartz. Inside the quartz, close to the surface of the front prism face, there are two wonderful negative crystals (see the detail picture below). These are small quartz crystals which either formed next to or on the larger crystal but were swallowed up as the large crystal kept growing. These aren't exactly rare in Herkimers, but they aren't exactly common, either. And to have two so close together and so well formed and so visible IS rare. This piece measures 8 x 10 x 4 cm and the large herk is 2.3 cm long.