Vintage turquoise & seed pearl brooch/pendant necklace sterling silver? filigree

Description

Intriguing and imposing large pendant brooch.  Features large 1 inch turquoise cabochon, surrounded by tiny seed pearls and filigreed metal frame.  It is stamped on the bail, but unreadable; possibly a sterling mark.  Pendant is overall a little over 1 1/2 inch.  It is hung on a 28 inch chain which may not be original.
Very good condition; at a guess this pendant/brooch would be mid to late Victorian.
Please look over all pictures and feel free to ask questions.