elder kneels on grassy lawn holding hand sample of banded iron formation stone from rock garden

aged banded banding chemical chemistry chert club coloration earth education evidence fe3o4 ferric geochemistry geologic geologist geology geoscience hound hydrology iron learned life magnetite minerals model ore oxidation oxide oxidized oxigenation paleophile petrology product quartz reactant reaction reddish rock rockhound science sedimentology senior share sharing silica silicate sio2 sio4 society strata tetrahedron thinning time undefined waste