The spherical, approx. 250 million year old porphyry formations, popularly known as "Schneekopfkugeln" due to their shape, were first and mainly found on Thuringia's second highest mountain. Mostly occurring in an ideal round shape, snowcap spheres are usually completely or partially filled with agate, chalcedony and/or quartz crystals. Because of their beauty and variety of colors, they are coveted collector's items.

Special specimens can be admired and purchased in the museum.