Identifying Your GNS&CO Amethyst Brooch: History & Value

Question
Hello there!  My sister purchased a huge broach.  It is rectangular, rather ornate, with a very large clear colored amethyst looking stone in the center.  The only mark on the back side is the GNS&CO mark.  It apears to be brass but is perhaps copper (at least underneath).  Someone has rubbed a portion of the patina of brass away in a corner and it appears copperish in color.  Is there anywhere I could find out more about this broach?  To find out what metal it is?  To find out whether the stone is authentic?  Does this mark mean a manufacturer?  Do they have a site where to look up this broach?  Would it help if I could get a picture of it and send it?  Thank you very much in advance for your time and expertise in these matters.  I did take it to a jeweler and they did not seem to know what to do with it.  Should it be cleaned - and with what?  Thank you again for your help.  I shall be looking forward to your answer!

Answer
G'day Lisa and many thanks for your query

The first concept you should understand is that of 'Is it Real?' because this makes it important in valuing anything.

Jewelers (99.99% of the time) will NOT put a good stone in a poor setting. That is to say - an Amethyst of this size would not be put in a base metal costume jewelry mount.

And likewise, a large paste (glass) stone would generally NOT be mounted in gold. So in that case - it has to logically be a typical Fashion or Costume jewelry item of no great value.

The stamp is simply the manufacture Mark but as there is NO central registry for hallmarks or Makers mark (anyone on the world can make jewelry and they don't have to comply with USA standards) means the item could have been cast from anywhere.

Sorry I can't help and further than that. Your best bet it to check places like eBay for something similar because costume jewelry was made in their thousands so something like it may turn up. Alternatively there is a new site called Christian David's Fashion Jewelry at:
http://www.fashion-jewelry-online.com/ which may get something like this from time to time.

I wouldn't waste any good money on finding out though. Keep it simple and if your local jeweler can't help you when he has it in has hands - it means it "ain't genuine...."

Hope this helps.