FMS Sponsored Collecting Trip to Minerva Mine, Cave in Rock IL - My Best Find from that Night

Contributed by: Mark Cole
Date: Apr 9th, 2026
Locality: Minerva No. 1 Mine, Ozark-Mahoning group, Cave-In-Rock Mining Sub-District, Hardin County, Illinois, USA (See on Mindat)
Size: 4.5 x 2.5 x 6 inches
Weight: 2.25 lb

Description:
As a birthday present for me, the FMS sponsored a collecting trip to the famous fluorspar district in Illinois around Cave in Rock (actually, I do not think they knew it was my B-day beforehand - I just got lucky). We spent the day at the Ben E. Clement Mineral Museum (have not gone? Why not??? The best fluorescent displays this side of Franklin.) Howie Green, FMS VP, gave an excellent presentation on mineral collecting in Greenland. There were several folks trading rocks, and it was a great greet and meet - about 25 people from the Midwest area, as far south as Florida and east to New York.

As evening came near we all hopped in our trucks and caught the ferry to Cave-in-Rock, and onward to Minerva. Some of our group got caught in the (unbeknownst to us) parade they happened to be holding that day - what a traffic jam (but Howie got some quality time with Miss Fluorspar - see photo at end of this post). I was lucky and got to collect some in the daytime, found a few boulders and whacked away at them. Came away with some very respectable pieces of calcite and fluorite (with a mysterious blue I\'ve not seen before - probably also fluorite). This is one of my best.

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(Do not miss the trip report about this visit in the FMS UV Waves newsletter 2018, Volume 48, no. 1)

Originally posted by Mark Cole on Nature's Rainbows in 2017.