www.925-1000.com

I believe that it is from St. Petersburg, not absolutely sure of date.

You would do all readers a big favour yourself included if you clean the marks before you show them. The marks are a smudge. Nonetheless, my best shot would be without any guaranties that it is Moscow and not St. Petersburg. The hallmark seems to be from before 1882. The maker's mark looks like С.Г., and that could be Semyon Gorshkov. He was active in the mid 19th century in Moscow. But as I stated earlier: Pure speculations.... Clean the marks and we'll take a new look...

Thank you, I will.

Hope this is better. The cyrillic character on the left part of the maker's mark is still a bit obscured on the bottom but the point on the top looks idiosyncratic and might help you sleuths. Thanks again for your help.