If you've ever gone to Fossilklopfplatz you will often unexpectedly find them closed. I suggest instead going to the fossil & gem store downtown in Pottenstein to buy pretty stones and fossils. They are extremely reasonably priced & even have jewelry, book ends, & keychains.
If the actual store is ever closed when you go they allow customers to pay for the items by putting your money in the can that they have outside. It is based on an honor system, so don’t abuse it. Although the selecting outside is more limited, they still have really interesting & beautiful pieces laying out on the tables.