Sign of the Deathly Hallows



Gellert Grindelwald’s mark is a triangular rune that Dark wizard Gellert Grindelwald used as his sign, though it is actually the symbol of the Deathly Hallows.This "double association" seems to be reference to the Swastika, a sacred Hindu symbol of the sun, later adopted as the symbol of Nazi Germany.

History
Harry Potter noticed this symbol in 1997, when Viktor Krum pointed out that Xenophilius Lovegood was wearing it around his neck at Bill Weasley and Fleur Delacour's wedding. Viktor told a disguised Harry that it was Grindelwald's sign, which he had carved into a wall at Durmstrang Institute when he was a student there. Some students later copied it into their books and clothes, thinking to shock and to make themselves impressive. Others who had lost family members to Grindelwald, including Viktor, corrected them. Harry found it difficult to believe that Mr. Lovegood would wear something related to the Dark wizard, but Viktor claimed he would duel the man if it would not spoil the wedding. He later confronted Xenophilius over the symbol, arguing with him before storming off.

Later, during the Christmas holidays, Harry, Ron Weasley, and Hermione Granger visited the Lovegoods' house to speak to Xenophilius about the symbol, which Hermione had found on the grave of Ignotus Peverell in Godric's Hollow and in the copy of The Tales of Beedle the Bard that Albus Dumbledore had bequeathed her. Xenophilius revealed to the trio that the triangular symbol was actually a sign of the Deathly Hallows. It represents the Cloak of Invisibility, the Resurrection Stone, and the Elder Wand.