Barite Rosettes from the Linwood Mine, Buffalo, Iowa
Located on the banks of the Mississippi River in Buffalo, Scott Co., Iowa, the Linwood Mine is one of the largest underground limestone mines currently in operation in the United States. For decades, the Linwood Mine has produced lovely display quality specimens of calcite and barite. In the past several years, the Linwood Mine has also produced some spectacular fluorescent mineral specimens. In November of 2020, the mining operation opened up a pocket containing barite specimens having a very unique, arborescent growth habit, consisting of clusters of branching, intergrown barite rosettes. The pocket was named the November Rose Pocket. In addition to their unique growth features, these rosette barites are also brightly fluorescent under UV.
The specimen featured here provides an example from the November Rose Pocket. This piece measures 12.1 x 9.3 x 6.7 cm, and weighs 736 grams.
Branching intergrown rosettes of barite produce a very aesthetic arborescent specimen from the November Rose Pocket. The above image shows the specimen under short wave UV (253 nm).
The November Rose barites are also strongly phosphorescent. The photograph above shows the afterglow of the same specimen following exposure to short wave UV (254 nm).
A similar, but brighter fluorescent response is seen under long wave UV (365 nm).
Following exposure to long wave UV (365 nm), vivid green phosphorescence/afterglow is seen.
Same specimen shown under visible light. This piece is approximately hand-sized.