Hi, @rita-klein – from what these mammal experts say we can update your classification and geochronology sections a bit. Kingdom Animalia > Phylum Chordata > Class Mammalia > Order Perissodactyla > Family Equidae > Genus Equus. Eon Phanerozoic > Era Cenozoic. Let me know if you need any more help, Jen

@rita-klein This is an Alumina ball used in a ball mill to grind any number of materials used for coatings. When I worked in the appliance industry we used these in huge mills for grinding the glasses and clays used to make porcelain enamel. The ceramics industry uses them for this purpose as well. They are commonly found in any area where…[Read more]