19th century articulated gold and gemstone necklace

An 18 carat yellow gold openwork necklace with a frieze of volutes, set with rose-cut diamonds and green stones on paillons, five of which are held in pendants. It comes in two parts. This necklace is presented in a green leather case bearing the initials PB and a marquis's crown. French work from the 19th century.
Hallmark: eagle head, 18 carat.
Weight: 1.23 oz.
Dim: 15.15 in.