OK, so it's a C C marking in a rectangle, so it's 1865-1935, but it's the other marks that I don't know. This is a hammered tumbler, if there was a number in a diamond shape then it'd be the silver layering or weight, according to the a_christofle page, but there are three numbers on here, none in the diamond. There're two sevens, and a 91, one of the sevens being almost merged into the 91. Is one of those a maker's mark? Is there any way to identify the year, line, or maker? Is there any information that can be ascertained?
Thanks in advance.