Minerva No. 1 Mine, Cave-in-Rock, Hardin County, Illinois, USA

Dimensions (H x W x D)

7 x 8.5 x 5 cm


286 g

Description & Provenance

Fluorite from Illinois distinguishes itself as some of the most strikingly zoned of all fluorite, rivaled only by occasional finds from the Yaogangxian Mine in China. The availability of certain trace elements during the formation of the crystals makes for some of the most awe-inspiring color combinations known for the species. Illinois specimens are further distinctive against other zoned examples from other localities because they never contain the color green. In order for fluorite to exhibit the color green, it must have access to the native element yttrium during its growth, however it is completely absent in the geology of the region. Besides the absence of green, other colors are all well represented, often in mesmerizing combinations, making for some of the most distinctive specimens ever recovered.

Of the many collections specifically centered around fluorite, the Ross C. Lillie collection, which focused exclusively on Illinois fluorite, has garnered world-wide acclaim. It was passionately collected, expertly curated, and extremely well-managed by Ross C. Lillie who was the exploration geologist for the Ozark-Mahoning Company from 1979-1984. With the advantage of being at the heart of production, Lillie was able to cherry-pick specimens’ right from the source. His discerning taste and devotion to minerals allowed him to amass one of the greatest fluorite collections known to the collecting community.

This impressive specimen was recovered from the mine in January 1991 in the Rosiclare Level of the Minerva No.1 Mine. It features a primary crystal of lustrous, cubic fluorite. The crystal has formed with distinct edges, large faces, and excellent translucency. It also boasts outstanding, electric blue coloring, as well as distinctly purple color zone within the crystal. This is a great example of fluorite from a famous locality. Notably, the area is depleted of this particular variety, so specimens like this one have become rare, modern American classics.

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