HELP ME IDENTIFY AGE OF JEWELRY

[gemee]

Hello,
I recently acquired what I was told as a "Celtic" brooch. After thoroughly scrutinizing this piece,I am convinced that it is much older. It looks like something that could have come from an ancient shipwreck. I am going to enclose a couple of photos for you, and see if you might give me your "feeling" on this piece. I have figured out that someone wired on a brace and soldered a pin and a clasp on this brace, so as to not damage the gold, (which acid tests to be high carat 20-22K). Also originally it appeared to have enamel work, that has all but disappeared over time. It measures 3x2 inches and weighs 47 grams.
If you can think of someone who can advise me on this piece, I would love to make contact with them, as I am anxious to learn more about this intriguing piece.
Here are some pictures;

[dneyedli@res1.mts.net]

Doesn't look as old as Celtic to me, more like medieval to 300 years ago span. I'm by far no authority on this piece.
I do recomend posting your brooch on U.K. DETECTOR NET. They would definitely know.
Dave.

[gemee]

Thank you Dave! I will post on that board. I apprciate your advice!