Sterling Silver Diamond Key Heart Pendant Necklace. 0.03 Carat Total Diamond Weight. This pendant comes with an 18 inch sterling silver chain as shown. Alternate chain length, weight, or style options are available. Open the door to her heart with this charming key necklace. The whimsical design is crafted from polished 925 sterling silver with a recurring heart motif and .03cts of pavé diamonds for a pop of sparkle.