As with many objects recovered from the Monitor’s wreck site, this fragment of a cast iron wheel was recovered almost completely contained within a thick mass of sediment and concretion.
X-radiography of the concretion revealed that the artifact had completely “graphitized”. In other words, all the iron within the wheel had corroded away and what remains is a mixture of carbon and corrosion products. In the image below, you can make out the faint outline of the wheel handle within the concretion.
Although “graphitized” cast iron material is quite frail, careful cleaning and removal of the the sediment and corrosion products around the wheel uncovered three tapered oval-shaped spokes connected to the handle as well as revealed flashing lines left on the the artifact from the casting process.