This is a beautiful fenster quartz (window quartz) crystal from Brazil. It developed by skeletal growth – the edges grew more quickly than the faces. Sometimes the faces caught up with the edges and closed fully, while at other stages of the crystal’s growth, they did not – the completed faces are “windows”, behind which there are hollows. Quite often, fenster quartz crystals have raised edges and uneven growth at their outer surfaces. However, this crystal has mostly closed all around, with completed outer faces and only a couple of small skeletal surfaces. It is almost all smooth, glassy window surfaces, and through those, you see all of the skeletal growth patterns. This is key, since most crystals with skeletal outer surfaces are quite damaged (skeletal areas are fragile and prone to damage).
This crystal has top lustre and sharpness. It is in excellent condition, a tiny chip at the termination, and small chipped spots in the skeletal surfaces. A beautiful cabinet specimen from the John S. White quartz collection.