This piece is unique due its 'cocoon,' of attractive green Prehnite. The Amethyst has inclusions of small flecks of Hematite. There are purple and black zoning bands near the top of the Quartz. I have seen thousands of these crystals hit the market over the last 14 years, and this is the best prehnite associated specimen I've seen during that time period. Crystals from this area are often misidentified as being from "Brandberg, Namibia," which is actually a deposit within a nature preserve in the same district. The Goboboseb mountains, in the Erongo region from which this cluster was found, is know for its remoteness, as the nearest water source is over 35 kilometers away. The host basalt has been dated to over a billion years old. I have discussed this with geologists, who have theorized that Quartz crystals from the Goboboseb mountains have probably been crystallized for over a Billion years!  On the top left face of the Quartz crystal the surface has slight etching due to Prehnite that had been removed from a small portion of that face.