Gilbert Ring

The Gilbert Rings are one of the three Gilbert Inventions created and used by Johnathan Gilbert, back in 1864 along with the Gilbert Compass and Gilbert Device. Although the pair resemble ordinary heirloom rings affixed with a black stone, they are in fact enchanted objects spelled to protect its non-supernatural wearers from death by supernatural means, allowing them to resurrect upon being killed.
They were secretly enchanted by the witch Emily Bennett and worn by Johnathan Gilbert in 1864 and, since then, the rings have been passed down through each generation of Gilbert men, with the exception of Samantha Gilbert, the only female to own a Gilbert ring. It is unknown if Emily knew of its side effects with regular use.
However, its wearer can be killed should the rings be cut off or forcibly taken off. Grayson and John Gilbert inherited the rings from their father. John gave his own ring to Isobel Flemming, who then gave it to Alaric. John then took possession of Grayson's ring after the latter's death. There are only two known Gilbert Rings in existence. Both rings are made with black stones. Alaric and John's former ring is now bound to the last White Oak Stake, making it indestructible, leaving only one known ring left.