the letter F on clasp ?

[suprdave]

found a chain that said 120 12 kt on it 120 links, but on the clasp that hooks it to itself had the lletter F in a circle. im curious what the F stands for any help would be appreciated. suprdave

 

[jeff of pa]

May be "George H. Fuller" Mark

http://www.illusionjewels.com/costumejewelrymarksf.html