How old is this brooch? testing as gold and garnet

Hello! This brooch came in an antique jewelry lot that I picked up at auction recently (has a few condition issue but still pretty!). It is testing as 14K, is it normal to have all of those darker solder-like spots on gold? Or is it likely to be plated? The centre cabochon is testing as garnet on the Presidium, the dangle I'm not sure (it doesn't seem to be garnet, possibly paste?). Hoping you can help me with age. Thanks as always!

 

Early twentieth, it’s very art nouveau. The solder may not be gold.

 

Great, thank you!

 

Sweet, but the damage on the front is a serious problem

 

so's the reconstruction on the back..!!!

someone tried hard to save it !

 

Yes, it's a little bit of a dog's dinner sadly