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

Dimensions (H x W x D)

6.3 x 10.4 x 6.1 cm


423 g

Description & Provenance

The fluorite found in the Illinois-Kentucky Fluorspar Mining District is a product of geological development that took place approximately 200 million years ago. The area was flooded with intensely hot water that was rich in fluorine and various other dissolved chemicals. This brew of elements flowed through fault lines and fractures within the earth’s surface. By the time it reached the area known today as Illinois and Kentucky, it had cooled to the perfect temperature and was in the ideal environment to crystalize into fluorite. Illinois was an exceptionally prolific producer of fluorspar for the United States of America and was mined from the early 1800s until 1995. It is considered a classic locality among mineral collectors and boasts well saturated fluorites in an array of colors.

This is a superb example, once a part of the famous Ross C Lillie collection. Lillie was an exploration geologist for the Hardin County mines for many years and, thankfully, had the foresight to save mineral specimens while working in the mines, taking exceptional notes as he went. After becoming intimately aware of all the area was capable of, he also acquired and traded specimens with other collectors, making sure to represent all the most unique and attractive characteristics. Hardin County was a prime source of outstanding, color-zoned fluorites of exceptional quality, being uniquely familiar with its output, Lillie was able to cherry-pick, and identify the best material. By the time he de-accessed his collection, he had curated it to be an ultimate representation of the best from the area.

This is a fantastic fluorite floater (meaning that it has no extraction points and is fully crystalized all the way around), found in an orebody of Hardin County in April, 1990. It was RCL1425 in the Lillie collection. It is composed of two primary, cubic crystals that have intergrown with one another at one corner. Instead of fully continuing their cubic form at the bottom, both have a recrystallized lower half. This unusual, sculptural form is incredibly symmetrical, and that symmetry is mirrored by the crystals’ color zones within. Yellow cores transition into thin lines of purple, then indigo, and then a lilac-blue. Those crystals rest upon a small pedestal of fluorite that gives them the appearance of defying gravity. Its form and zoning give the piece incredible dimensionality. Some liken it to a bird with its wings spread and ready for flight. Others say it looks like an exotic butterfly. The specimen is further enhanced by its translucency and high luster. Without plans to re-open the mine, pieces of this quality and beauty are a rarity that grow even more scarce with time.

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