sorry I don't know! I am not really an expert either - although striving to become one.... :-)
The way I have figured out the 84 is via the website http://www.omniglot.com
and then checked on this website the silver content http://www.925-1000.com/a_Standards.html
Also I believe somebody mentions the Persian 84 in the forum.
Your mark looks more like a city mark - but really as I said - I am not an expert!