Late 19th/early 20th Century Opal and Ruby Necklace

"A late 19th/early 20th century opal and ruby necklace
The front composed of a series of graduated oval opal cabochons with ruby collet spacers suspending alternate opal and ruby two stone drops and single opals on knife edge bar crescent mounts, to a ropelink neckchain, approximately 36.5 cm. long" - Christie's