You are right about these marks being a mystery - noone can decipher these marks as they are not complete because of the very poor re-sizing job. The ring has been resized which means the ring band has been cut through to either increase or decrease the size and for some reason the jeweler has cut right through the middle of the hallmark. Apart from any personal connections to this ring, it's monetary value will be in the scrap gold value, if it is gold or as a great example of a very poor ring resizing job.
