Put-in-Bay celestite (Crystal Cave)

A winemaker dug a well in 1897 and broke into a cavity lined with crystals three feet across.

Gustav Heineman had emigrated from Baden-Baden in 1887 to Put-in-Bay on South Bass Island in Lake Erie, where he set up a winery. Ten years later he sank a well beneath it and at thirty feet down hit a large vug. The walls were covered in extremely large, well-developed tabular crystals, which turned out to be celestine, a form of strontium sulfate.

The first instinct was to mine it. Much of the celestine was taken out for the manufacture of red fireworks, which get their colour from strontium used as a pyrotechnic colorant, and the cave you can walk into today is a good deal larger than the original cavity because of what was removed. Heineman then stopped the mining and turned the place into a tourist attraction instead.

That decision saved the family business. The Crystal Cave drew enough visitors that the Heineman winery survived Prohibition on tourist revenue, which is not a sentence you get to write about many mineral localities.

The cave remains open for tours, and the celestine crystals in it reach up to three feet across, lining the limestone walls of the thirty-foot-deep chamber. Ohio's Department of Natural Resources lists it plainly in its state rundown of mineral occurrences: Crystal Cave, South Bass Island, Ottawa County, celestine crystals in cavernous dolostone.

The two descriptions of the host rock differ, limestone in one account and dolostone in the other, which is a common enough disagreement in carbonate country and worth noticing rather than smoothing over.

This is a commercial attraction on private ground, so it is a place to look rather than to collect. Ohio DNR notes generally that collecting may not be allowed at the sites it lists and that you should ask the park or the local authority first.