Strontianite from the Historic Cave-In-Rock Mining District
Contributed by: Michael Crawford
minID: 2A6-HWF
Date: Apr 21st, 2026
Locality: Minerva No. 1 Mine, Ozark-Mahoning group, Cave-In-Rock Mining Sub-District, Hardin County, Illinois, USA (See on Mindat)
Size: 9 x 5 x 14 cm
Weight: 293 g
Description:
Strontianite is an uncommon strontium carbonate mineral that was sometimes encountered during fluorspar (fluorite) mining activities in the historic Cave-In-Rock mining district in Hardin County, Illinois. Although the last of the famous fluorspar mines in Cave-In-Rock closed in 1995, well crystallized specimens of strontianite can still occasionally be found at rock and mineral shows in the midwestern states. This is a fine example from the Minerva No. 1 mine in Cave-In-Rock. This specimen was mined by Ross Lillie in April 1990. It consists of a large aggregate of radiating, snow-white, acicular crystals of strontianite with no matrix. Shown here under short wave UV, this specimen displays a similar bright blue/white, fluorescent response under both shortwave and longwave UV.
Originally posted by Chris Clemens on Nature's Rainbows in 2019.
Summary of luminescence responses:
Strontianite (Mindat) (RRUFF)
- Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: White