Sterling Silver Black Onyx Beaded Collar Necklace Sterling Silver Black Onyx Beaded Collar Necklace. Genuine gemstone necklace. Gemstone beads are intricately woven over a clear rubber collar and finished with a magnetic clasp. Position the clasp at the back for an all-bead necklace look or attach one of our matching sliders, sterling silver Pendants or drops drop and turn the clasp to the front to present an attractive, contemporary design element. Specifications: Black Onyx Beaded, .925 Sterling Silver, Made in the USA, Available in 16 and 18 Inches