E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
An unlucky possession, something that brings evil to all who possess it. Harmonia was the daughter of Mars and Venus. On the day of her marriage with King Cadmos, she received a necklace which proved fatal to all who possessed it.
The collar given by Alphesiba (or Arsinoë) to her husband Alcmæon was a like fatal gift. So were the collar and veil of Eriphyl, wife of Amphiaros, and the Trojan horse. (See FATAL GIFTS.)