Sauer Birthstone Necklace in Gold: Ready to ship within 2-3 business days. A thoughtful gift for anyone who loves their birthday (you know the type), this striking pendant—done in eighteen-karat gold and onyx—features a bezel-set birthstone of your choice sitting pretty in the center. Don’t miss the corresponding month carved into the side.16.5" 18k yellow gold chain; 18k yellow gold and onyx pendant Birthstone Guide: January: Garnet (0.33 cts) February: Amethyst (0.253 cts) March: Aquamarine (0.2 cts) April: White Topaz (0.2 cts) May: Emerald (0.2 cts) June: Pearl (0.26 cts) July: Ruby (1.0 cts) August: Peridot (0.196 cts) September: Sapphire (0.287 cts) October: Tourmaline (0.2 cts) November: Citrine (0.18 cts) December: Turquoise (0.346 cts).