If you try searching "word SILVER", there's at least 38 pages, most of which probably won't help. Around page 16 or so, found this thread to show you clearly how word SILVER is seen around the right side of your maker's "Bird over S" logo mark:
http://www.925-1000.com/forum/viewtopic ... VER#p89990
Obviously it is preceeded by another word, and yours seems to start with "S". Maybe the maker name again. Maybe Sterling. Maybe a line name. Could take a lot of work to find a similar mark to yours. And several countries have used the SILVER word.
Thread reference: "word mark SILVER"