Art Deco Glass Necklaces + Amber

I bought these three necklaces and I'm trying to figure out their age and origin. They're all strung on thread; the grey necklace's thread looks like silk to me, but I'm not sure about the others. The amber necklace appears to be made of tiny pieces of amber that have been fused together; does it have any value? I paid 12 euros total for all three, so I'm trying to figure out if I got a good deal or not.

 

Looks like a good deal to me.
The amber necklace looks like 'amberoid' (I know...), pieces of amber in artificial resin. It is sometimes confused with pressed amber, which is amber pieces bonded together through heat, no artificial bonding agent. They can look similar.

 

Thanks.
That makes sense. It doesn't have all those fish-scale bubbles I had seen in heat-treated pieces.