What is the core of Harry's wand?

Harry Potter’s wand has a phoenix feather core—the feather came from Fawkes, Dumbledore’s phoenix. Ollivander notes phoenix feathers produce powerful magic but can be choosy about their user. Fawkes gave only two feathers; the other went into Voldemort’s yew wand, making Harry’s holly wand and Voldemort’s “brother wands.” This connection explains the Priori Incantatem effect during their duel in the Goblet of Fire. To remember: phoenix = Fawkes, fire and rebirth—like Harry’s resilience. By contrast, dragon heartstring often favors power and volatility, unicorn hair is consistent and loyal, and Thestral tail hair is famously in the Elder Wand. So, phoenix feather uniquely ties Harry to Voldemort and to themes of renewal.