Look like either hazelnuts or chestnuts? I read one article that said some old bakelite was painted and maybe this is the problem there is a tiny bit of white showing on leaf edges so maybe the white was painted over.
I tried the hot water test and do get some odor. The leaves are very light weight. Whatever, it is a real cute set. The chains are celluloid I believe. The necklace choker measures approx. It has an old discolored clasp. The pin branch measures approx. It has a drop of about 1-1/2 it has the old c clasp. The item "Vintage Celluloid Bakelite Leaves Hazelnuts Pin and Necklace Set" is in sale since Sunday, November 21, 2021. This item is in the category "Jewelry & Watches\Vintage & Antique Jewelry\Jewelry Sets".The seller is "ccc0336" and is located in San Jose, California. This item can be shipped to United States.