This is a very nice, 5.5" cluster of long, "cactus quartz" crystals mined in the Magaliesberg Mountains of South Africa. There are over a dozen individual points, many over 2 inches long, with excellent terminations and color. The base of the rock has been cut flat, so that it sits nicely on a hard surface. A really phenomenal piece.
Cactus quartz, often also referred to as spirit quartz, is a variety of quartz characterized by second-generation druzy crystals growing on the faces of larger quartz crystals. The small second-generation crystals point away from the prism and their orientation is not related to the crystallographic orientation of the central crystal. Cactus quartz is currently only known from the Magaliesberg Mountains region of South Africa, and comes in a variety of shades ranging from white to deep purple to orange colorations. The deep purple amethyst points are the rarest and most coveted by collectors.