A double row of large emerald cut topaz rhinestones separated by round stones. All are prong-set, clear and sparkling.
The smaller stones on the chain might be showing their age. They are not dark, but some might be getting a tiny bit cloudy.. only seen with a microscope.
This is most definitely unsigned Weiss dating 1950's – 1960's
16" long and slightly over 1/2" wide.