Amulet of the last stands

This is a magical steel necklace, with a green alexandrite in the middle. It has a very faint smell of fresh blood

Once a dawn, when the wielder reaches 0 hit points, a flow of energy powers through them, setting their hp to 1, and giving them 15 bonus hp until the enf of their next turn

When activated, the alexandrite changes its color from intense dark green to a half transparent pruple-ish color, and it errates a smell of rotten flesh for about a minute

Notes: Healing, Buff, Combat, Necklace, Jewelry