Madonna and Child Cameo Necklace with Upcycled Recycled Repurposed Vintage Prehnite Gemstone The many different shades and cuts of Prehnite gemstone beads that make up this necklace are stunning and perfectly compliment the cameo image of the Madonna and Child. All the Prehnite gemstones in this piece were part of a broken vintage hand knotted necklace that I upcycled to compliment the wire wrapped cameo focal. Necklace is 18 inches long with a 2 inch long 1.125 inch wide wire wrapped cameo drop.