Pisolite - a sedimentary rock made of pisoids.

Pisolite - a sedimentary rock made of pisoids. A pisolite is a sedimentary rock made of pisoids, concretionary grains typically of calcium carbonate that resemble ooids but are more than 2 mm in diameter. The rock, an excellent example of Pisolite, was purchased while living in Prague and will come with the card. It is originally from Karlovy Vary, CZ, which is famous for its hot springs. The mineral deposits in the area, including pisolite, are part of its unique geological environment.