From The Grey House:
“Natalie. Don’t disappoint me.” He did not hide the annoyance in his voice. It was the same voice he used before whipping or beating her.
Not wanting to be beaten yet again, Natalia gritted her teeth. If only Bethany wasn’t in danger… but Vincent was taking care of that; she had to play along until the vampire could act. Natalia, her mother’s face swimming before her, reached around her neck to the clasp. Sighing, she undid the clasp but didn’t move her hands. The necklace had been around her neck since age ten. She still remembered the day her mom showed her how to make it and the songs she needed to sing to weave her will into the beads. She felt something unwinding in her head. Natalia suspected it might be the control she had over the people she hypnotized.
Remembering how she felt when her mother died and gave back her memories, Natalia reeled the feeling in and clamped a hard mental hand on her control. Understanding gripped her. It was not just the necklace, but her will that made the hypnosis work. She could keep control of those she hypnotized without the necklace, but probably still needed it to get someone under her control. Knowing she could later retrieve her mother’s necklace that still lay in her jewelry box, Natalia made her decision. She opened her eyes, slipped off the necklace, and handed it to Zechariah.