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PhotosGalena - Minerva No. 1 Mine, Ozark-Mahoning group, Cave-in-Rock, Cave-in-Rock Sub-District, Illinois - Kentucky Fluorspar District, Hardin Co., Illinois, USA

13th Sep 2016 16:29 UTCJamison K. Brizendine 🌟 Expert

I came across this specimen while looking at several specimens, but I don’t believe it is a Minerva No. 1 specimen, let alone one from the Illinois-Kentucky Fluorspar District! These are the reasons I think it is not from here:

First, galena was a rare mineral from the Minerva No. 1 mine and there are very few documented galena specimens from this mine. In fact, the major producers of galena during the 1970s was the W.L. Davis-Deardorff Mine and the Hill-Ledford Mine. Since we have a date of “1972”, we can rule out the Annabel Lee Mine and the Denton Mine as possible origins for this specimen, as they were opened in the 1980s. Literature (Weller et al. 1952) even suggested that lead was lacking from the ore itself at the Minerva No. 1 mine.

Second, the “fortification style” galena crystals have never been reported from the Illinois-Kentucky Fluorspar District. Galena from both the W.L Davis-Deardorff and the Hill-Ledford Mine (since we have date of 1972 prior) were typically on a quartz rich matrix, sometimes with sphalerite and almost always with some fluorite. The galena from these two mines though, were typically simple cubes. “Fortification style” galena crystals were common from the Tri-State District (OK-KS-MO) when those mines were operational.

Third, the “calcite” on this specimen is not calcite at all, but dolomite (not to mention that the label says dolomite and not calcite!). Dolomite was reported from the Minerva No. 1 mine, but as closely packed rhombohedral crystals (Lillie, 1988). Dolomite from Minerva No. 1, though was typically formed after fluorite crystallized, which is obviously not the case here. Dolomite from the Tri-State District though, was exceedingly common and often seen with both sphalerite and galena.

Finally, notice the label. The label stated its origins as coming from “Cave-in-Rock” and not the Minerva #1 Mine directly. Specimens from both Cave-in-Rock District and the Tri-State District often co-mingled between collections and dealers, and I believe that this was the case here. To me this specimen was mined in one of the mines in the Tri-State District, then re-labeled as Cave-in-Rock, either by Glen Williams or Jaime Bird, when Jaime acquired the specimen from Glen. This is a good (and even a historical example) of a common switch-up that happened frequently. We are lucky that the documentation even existed.

It’s a very nice specimen, but I doubt its origins as a galena from the Minerva #1, much less the state of Illinois.

References Cited:

Weller, J.M., Grogan, R.M., and Tippie, F.E. (1952) Geology of the fluorspar deposits of Illinois. Illinois State Geological Survey, Bulletin 76: 1-147.

Lillie, R.C. (1988) Minerals of the Harris Creek Fluorspar District, Hardin County, Illinois. Rocks and Minerals: 63 (3): 210-226.

13th Sep 2016 20:15 UTCRob Woodside 🌟 Manager

Thanks very much Jamison. Message sent

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