“Witness that kunckleheaded young man at your brother’s wedding who attacked me for sporting the symbol of a well-known Dark wizard! Such ignorance. There is nothing Dark about the Hallows– at least, not in that crude sense. One simply uses the symbol to reveal oneself to other believers, in the hope that they might help with the Quest.”
—Xenophilius Lovegood explaining the Sign of the Deathly Hallows
Xenophilius Lovegood’s necklace was an ornament that he wore to Bill Weasley and Fleur Delacour’s wedding. Some, like Viktor Krum suspected him of being a Dark Wizard, but actually the necklace simply bears the symbol of the Deathly Hallows to show that he believed in them and was used as a symbol to recognise other seekers.
The Sign of the Deathly Hallows is a triangular mark used as a representation of the Deathly Hallows, three legendary objects that allegedly, if united, would make one the “Master of Death”. The sign is actually composed of three separate marks that, united, make up the sign. The Elder Wand is represented by the straight vertical line, the Resurrection Stone by the circle surrounding it, and finally a triangle enclosing them both to represent the Cloak of Invisibility.
Due to its history, and the history of the objects that it represents, the sign has also picked up certain additional associations.