I've been searching for a couple weeks without success. I have a silver ring that has two very small marks, I had to take it to a jewelry store to be able to make out the marks.
The first mark is a hand.
The second one is a fancy looking J with a crown on either side. The two crowns and the letter J are in the same stamp.
Searching online I was able to find references to a hand mark being for Malta 1798-1801, but I don't know if this ring is from Malta or not.