Vitrine's gemstone necklace was worn by Candice Accola (Caroline Forbes) on The Vampire Diaries S5 E516 (aired on CW March 20, 2014). Spotted in the opening scene for the first two minutes of the show! What was even cooler, is that my name is Candice, and it was worn by Candice! Meant to be, huh?!
If you'd like your own TVD necklace, you can find it here. And below are the screenshots too!