Need Help With: "Mexican Sterling 1666, patent pend&

[LisaILane]

Hi, I need help identifying a mark on a necklace of mine. It is stamped on the hidden pinch clasp as "Mexican Sterling, Patent Pend 1666". I could be a little off on what i could read on the mark, this is the best i could come up with. I am am also looking for help figuring out what kind of construction it is and a time frame. I think this is old, but i'm not 100%. Any info you can provide is appreciated.

Thank you kindly!
Lisa

http://i324.photobucket.com/albums/k342 ... G_3799.jpg" onclick="window.open(this.href);return false;
http://i324.photobucket.com/albums/k342 ... G_3801.jpg" onclick="window.open(this.href);return false;
(admin photo edit - image too large - insert as link or thumbnail only - see Posting Requirements)