A beautiful specimen of cassiterite crystals decorating siderite base from the famous Viloco Mine, Bolivia. It displays deep black to smoky cassiterite crystals to 11 mm with a strong luster. The crystals are twinned, well crystallized and sharp. Yellow-brown lenticular siderite crystals densely cover the base. Some small but water clear and transparent quartz crystals are seen too.  In very good condition – some very small nicks. On acrylic base.
Fascinating!