This is a most unusual jewelry listing! It’s a necklace with matching bracelet made of Lumarith, a type of plastic produced by the Celluloid Corporation in 1937. The plastic is pierced to resemble lace. The bracelet measures 6 ¾” (end to end) and the necklace measures 15 ¼”. Super!
I found the production information for this item in a December 2008 edition of Country Living in the "What is it? What is it worth?" section. The value placed on a blue color necklace -- no bracelet -- was $130.00 (in 2008!).