Hello, This doesn't quite look like eggshell porcelain. Eggshell porcelain is practically transparent and has a thickness that is about half or a third of the wall of an average coffee cup. More often than not it is white or with a decoration on white ground.
I'm afraid this is not a Chinese mark, unless it is very new mass production. If it is Asian it would be more likely Japanese, but to me the type of item looks more like European/western porcelain. It could possibly be Chinoiserie, that is western porcelain imitating Chinese decorations. The overall impression is that it is not Chinese.
