Witherite

Mineral(s): Witherite, with minor Alstonite and Fluorite
Locality: Minerva No. 1 Mine, Cave-in-Rock Sub-District, Hardin Co., Illinois, USA

Witherite is a simple barium carbonate mineral that often forms in barrel-shaped crystals like this one here. This 3.7 cm tall witherite crystal towers among some smaller associated minerals towards its base: numerous tiny white rice-shaped alstonite crystals as well as blue and yellow fluorite cubes. I personally love the alstonite; I think it provides a neat accent to this specimen.