Certain ancient ceramics can be grouped in a special class, characterized by an outstandingly high percentage of ferrous iron. Their manufacture required firing in a constant and strong reducing medium, which perhaps but man on the road to obtaining metallic iron. The article describes several types of iron oxide compounds found in ceramics: Those that existed before the ceramics were made and probably came from sands or rich iron ores; several more or less hydrated oxides associated with the clay portion of the ceramic; and a small quantity present directly in the structure of the clays. While most Near and Middle-Eastern ceramics contained little iron, this was not the case with one group of a dark, metallic gray color, sometimes rust-spotted, which accounted for nearly al ceramic objects in ancient cultures in the north of Iran, Anatolia, and Greece.