Vintage exotic handmade silver necklace w green malachite stone

One of a kind vintage handmade exotic filigree necklace. With natural green malachite stone. Transformer - the pendant can be worn as a brooch / pin, and the chain can be used with other pendants. Stamped silver on the back of the clasp (not sure how much silver it contains). The pendant is also stamped, but I can't read it. It is likely made from some metal alloy. Darkened, which is part of the design. 16" chain necklace. 1.75" pendant / pin.