This is a very pretty Victorian book chain necklace. The center pendant has an oval, prong set, garnet colored stone (I assume it is a real garnet, but am not 100%). The stone has black enamel work surrounding it and book chain tassels hanging from it. It closes at the pendant with a slide-in clasp which works properly.
The chain measures 3/16 inch wide and 15 inches long from the clasp to the other side of the pendant. The length from the top of the pendant to the bottom of the tassels is 1.5 inches. The garnet measures about 5/16 x 4/16. The gold-fill shows some wear to the edges on the chain.