Dragon Brooch with the capital letters M M A

I bought this piece at a yard sale.
It may very well be plate, but it is a very nice piece.
It is clearly cast.
The scene is of a winged dragon with a bent tail and
what looks like a fish tail at its end.
If it is plate, it is very very thick
plate as there is no evidence of any wear on the piece.
The piece has attachments both to hang it as a pendant
and a clasp to wear it as a brooch.
Hopefully I can get a foto uploaded.
Anyone know what it may be?
The only identifying marks...hallmark? are the capital letters M M A
located at the bottom on the reverse side.