The silversmith firm Jakob Grimminger was founded in 1893, in Schwäbisch Gmünd, Germany. They were famous as manufacturers of fine modern silver in the 1930s.The quality and designs are always excellant, and tend to be very sleek!

Conclusion: Looking from left to right.

1) The Half Moon and Crown symbol is the sign for made in Germany after 1884, and was compulsory

2)  925 means the standard of silver is 925/1000 that is Sterling.

3) The letter G surrounded by a star is the symbol of  Jakob Grimminger.

Summary:

This is a hallmark of a piece of sterling silver made in Germany after 1884, by the silversmith firm Grimminger in Schwäbisch Gmünd.