Sealing wax

"Turning the envelope over, his hand trembling, Harry saw a purple wax seal bearing a coat of arms; a lion, an eagle, a badger, and a snake surrounding a large letter H."

- Description.

Sealing wax is wax material which, after melting, quickly hardens (to paper, parchment, ribbons and wire, and other material) forming a bond that is difficult to separate without noticeable tampering. Sealing wax is primarily used to seal envelopes or documents.

Hogwarts acceptance letters were closed with a purple wax seal bearing a large "H" and the four animals representing the four Hogwarts Houses.

Appearances

 * Harry Potter and the Philosopher's Stone
 * Harry Potter and the Philosopher's Stone (film)
 * Harry Potter and the Philosopher's Stone (video game)
 * Lego Harry Potter: Years 1-4
 * Pottermore