Tourmalated Quartz and Onyx Necklace

This is a 18 inch tourmalated quartz and onyx beads necklace.  The facetted tourmalated quartz beads are 10 mm and the onyx beads are 8mm.  All the findings are sterling silver.  The necklace has a 3 inch extension on it so the necklace can be made up to be 21 inches long. There is a matching bracelet.