A geode looks like a normal rock — but Jesus, Marie, it’s not just a rock, because it in fact contains a dazzling mineral display concealed within its interior. Similarly, Celina, Ohio seems like a fairly standard city of 10,000. However, hidden in the back of the unassuming Mercer County Library, you’ll find a mineral collection with almost a thousand specimens from all over the world.

The collection was amassed by Ron and Ruth Langsdon, residents of nearby St. Marys who spent 15 years collecting minerals from the comfort of their own home. Having never gone rockhounding in the field, they instead worked with mineral dealers to build a personal collection that numbers in the thousands. In 2006, upon deciding that they wanted to share their finds with the public (and presumably looking to clear out some space at home), they donated part of their collection to the county library so that they could be enjoyed by current and future generations alike.

The Langsdon Mineral Collection contains not only a a glittering array of colors, shapes, and sizes, but also remarkable items from mines now closed as well as rare specimens from China and India heretofore unidentified by Western mineralogy textbooks. It rivals the mineral collections of major museums in terms of quality, and is listed as one of the most notable public mineral collections in the world, alongside places like the Smithsonian and London’s Natural History Museum.

Starting with an initial endowment of roughly 300 specimens, the library’s catalog now contains over 900 items (all donated by the Langsdons) and the displays have been expanded to branch libraries in Marion, Mendon, and St. Henry.