The mark you found is very close, but not quite exact. I wonder if the mark on my cup comes from the same time period. I have no idea when it was made, or even which century, or what country. The mark is quite a mystery.
My apologies if this is posted to the incorrect forum. Searching the images, I was unable to find anything close to this. The mark appears on the bottom of a cup. It is a D in a dotted circle. That is the only mark on the bottom of the cup. There are no other markings. If any expert identifier could...