The Heart of Darkness was a black pearl shaped like a human heart, and as big as a human fist. It had become imbued with strong voodoo powers, and in 1943, it was sought after by Indiana Jones, George McHale, led by their guide Marie Arnoux.
Also hoping to gain the treasure was Boukman, the voodoo bokor; Edwin Gruber, a Nazi spy; and Yamada Hajime, a Japanese spy. The latter two believed that the pearl was not as important as the inscription on the case containing the treasure, which they believed was a Haitian invincibility formula, which would be extremely useful in wartime.
Legend had it that the Heart of Darkness was taken from an extinct oyster species and was once the centerpiece of a magic practiced by a family of witch doctors on the west coast of Central Africa before being taken during a tribal conflict, but not before a curse was placed upon it.
During a raid in the late 1700s, the height of the slave trade, a Central African woman was taken — most likely from the equatorial regions in Ngoyo, Kakongo, Ndongo, or Matamba, Indiana Jones would later suggest — who was very dear to the Manikongo, the ruler of one of the most important kingdoms. The Manikongo tried hard to negotiate with the slavers for her release, eventually offering them the Heart of Darkness.
The slavers accepted the offer but when the pearl was delivered, they killed the men who brought it, taking the pearl for themselves, as well as keeping the woman. They went on to sail to Hispaniola, but during the storm, their vessel was caught and wrecked in a storm off the south coast of Haiti, which was said to be a result of the curse. Almost all of the crew drowned and the cargo sank to the depths of the ocean, but a man managed to save the pearl and took it to the island of Zile Muri-yo where he buried it.