Daylight Amulet also called Daylight Ring is a piece of jewelry with a lapis lazuli gemstone enchanted by witches, to protect vampires from the sunlight thus, allowing them to walk freely in the day. Their werewolf counterparts are the Moonlight Amulets.
The witch who casts the enchantment can also temporarily or permanently undo the spell on the jewelry at their discretion.
Throughout the series, female vampires often wear bracelets, necklaces, or rings that possess a lapis lazuli gemstone, as opposed to male vampires, who usually just wear rings. The jewelry itself doesn't have to be worn as it was intended; as long as it the vampire is touching or holding it in some way, they are protected from daylight.