Caption:
Galena on Fluorite. Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral. Galena is one of the most abundant and widely distributed sulfide minerals. It has a Mohs Scale hardness of 2.5 - 2.75. Fluorite (also called fluorspar) is a halide mineral composed of calcium fluoride, CaF2. It has a Mohs Scale hardness of 4. Specimen Dimension: approximately 5.5 x 7 x 5 cm. Denton Mine, Southern Illinois, USA.