The item in the pictures is listed as a Chinese coin on eBay. I'm sure it's not, but what IS it? Diameter around 42mm, central rectangle 15mm x 11.5mm Reverse is blank
Looks like it might fit into the coin that is your avatar lol But yeah. I'm clueless... although, it does look really interesting!
I cannot identify "what it is" but maybe I can help a little with the inscription. The upper photo is upside down so I am reading the bottom photo. The inscription is read top to bottom and right to left. The top right and bottom right characters are "da ming" which means "Great Ming" and refers to the Ming Dynasty (1368 - 1644) of China. I am making an educated guess as to the top middle and bottom middle characters. They appear to be "Xuan De" which would refer to the reign of Emperor Xuan Zong of the Ming Dynasty. I cannot make out the top left character. In most cases this would be the character for "year" but the character on this object seems to be different. The character at the bottom left appears to be "zhi" which would mean "made". My best guess is that the inscription says "made in (year??) of the reign of Xuan De of the Ming Dynasty". The characters are in an unusual style so it is difficult for me to read. The only characters for which I am absolutely certain are the two on the far right referring to the Ming Dynasty. Finally, I can only attempt a translation of the inscription and am not offering an opinion as to the authenticity of the object.