This necklace is made out of a 19th century fusee' watch balance, a 3cm AA quality round cut Mozambique garnet with one stainless steel gear and two antique watch hands, one round brilliant cut diamond, .025 carat, clarity SI1 on an 18-inch gold chain necklace.
Wiki: horology
They're all very beautiful- and very old! This piece came off a 1860's-ish watch. It didn't have enough markings to identify it completely.