Barite

When this find was discovered it immediately was recognized as a future classic locality, not only for the calcites but also the barites. This example has a clear zoned center with alternating faces on the display(?) side being frosted by microscopic pyrite inclusions. The back faces are all super glassy. Displayable from either side. A few minor bruises which could be resolved with a dab of mineral oil. Ex Martin Zinn collection.

Locality: Linwood Mine, Buffalo, Scott County, Iowa.

Composition: barium sulfate