A stunning art deco crystal and silver drop necklace.

A beautiful Art deco necklace with clawset crystals and a large crystal drop. The stones are beautifully cut. It is has some hall markings at the clasp which I cannot make out. It measures 40cm in length with a drop of 5.5cm.The metal tests for silver. I have put a new silver bolt clasp on as the original clasp is missing. Please ask for any other details.