Russian Hallmarks and Letter Marks

by Paula
(Auckland, New Zealand)

I have recently purchased a ring on ebay. the stone is synthetic colour change sapphire. The ring is supposed to be Russian origin. the hallmark is AZ then 583 then another mark in a circle which I cannot make out but that is not koloshnik or hammer and sickle. What I found strange if the ring is Russian is that there is another mark which has been inscribed AGL 25641. this incription is facing the opposite way to the Hallmarks and the letter G does not feature in the Russian alphabet and I know because I have studied Russian. What do you think?