I have posted this elseware and I came to the conclusion it was an amateur peice. Looking at the sig it looks kind of like the one in the other topic, so I'm posting it here too...
At first glance, the item looks fairly new but looking underneath I can see dirt. There's also dust and dirt on the inside. However, there's no crasing as I would expect to see on such an item.
I think the mark says (STP), perhaps the funny looking "P" stands for pottery? The mark looks like pencil but does not rub off with a rubber.