Another impressive feature about vampires is their virtual indestructibility. During the transformation process, a vampire's cells become extremely hard, durable, and refractive, rendering their bodies nearly impenetrable. Vampires are noted to be exponentially more durable than "soft" humans. The strength of a vampires skin is described as harder than granite, and even diamond-hard. Their bodies are so hard that they are unable to be harmed by human weapons, and the only creatures capable of killing them are other vampires, or werewolves. Their teeth are also noted to be one of the few things strong enough to be able to cut through their skin, as are werewolf teeth. Because of this indestructibility, it is quite impossible for a vampire to kill himself. As a newborn, Carlisle attempted this in many ways including jumping from atmospheric heights, drowning himself, and starving himself, after all of which he was unharmed.