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Encyclopedia Dubuque


"Encyclopedia Dubuque is the online authority for all things Dubuque, written by the people who know the city best.”
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Affiliated with the Local History Network of the State Historical Society of Iowa, and the Iowa Museum Association.


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Crystal Lake Cave

CRYSTAL LAKE CAVE. Discovered in 1868 by James Rice, a LEAD miner in search of ore-bearing stone, Rice's Cave was found to contain a fabulous collection of crystals including argonite, travetine, satin stalagmite, stalactite, and calcareous spar. (1) Originally access to the cave was reached by riding in a bucket lowered by rope down a forty-five foot shaft.

Bernard Markus

Ownership of the cave passed to Charles Linden who named it Linden's Cave. In the 1930s, the site was developed as Crystal Lake Cave by Bernard Markus, a son-in-law of Linden. (2) Markus operated the mine as a tourist attraction from 1932 until his death in 1944. The ownership then passed to Herbert Knockel and his wife Evelyn, a granddaughter of Markus. In 1978 the ownership of the land passed to James and Doris Rubel.

It was Rubel who hired Dennis Flint of Dubuque to replace the high voltage lines first installed in the cave in 1940. The new lights were virtually the same as used in automobiles and are operated by a series of substations that transform the voltage from 110 to 12. The less heat generated helps prevent the growth of algae. Flint's background as a theater lighting designer also came in handy when deciding where to place lights which were operated by motion detectors. (3)

See also: CAVES

Red indicates the part of the cave open to visitors (2015)Photo courtesy: Jim Massey
Photo courtesy: Mike Avitt
St. Peter's Dome
Lost Gardens
The Bell




1. Oldt, Franklin T. The History of Dubuque County, Iowa. Chicago: Western Historical Company, 1880, Online: http://books.google.com/books?id=u9xDAAAAYAAJ&pg=PA464&lpg=PA464&dq=Burton%27s+Furnace+%28dubuque+history%29&source=bl&ots=0CkCGLFR0v&sig=a0Ou1vN3ew6nQUYoq2aOJsXF9Mg&hl=en&sa=X&ei=j3HVT5XALaP42QXVp9iFDw&ved=0CGgQ6AEwBQ#v=onepage&q=Burton%27s%20Furnace%20%28dubuque%20history%29&f=false

2. "History," Crystal Lake Cave. Online: http://www.crystallakecave.com/history.html

3. Dickel, Dean. "Cave Lighting Illuminated," Telegraph Herald, September 13, 1993, p. 3A

Pratt, LeRoy G. Discovering Historic Iowa, Iowa Department of Public Instruction, 1975