Te Pito Te Henua, or Easter Island, by William J. Thompson, , at sacred-texts.com
The implements of warfare brought to the island by King Hotu Matua and his followers were few in number, and in the course of time became broken, lost, or destroyed. The clans were continually at war with each other, but from the want of proper weapons the most desperate encounters resulted in little loss of life. Spears were improvised with heads made of the sharp edges of the calabash, but they proved in efficient weapons and did little execution. During the reign of Atura-ugi, the sixth king, a man living near the crater of the Rana Kau, while returning to his home after sundown from Temanevai, where he and his companions had been engaged in a useless struggle, stepped in the darkness upon a sharp stone that cut his foot like a knife. He carried the stone home with him, and in the morning found it to be black volcanic glass, which upon being broken showed vitreous edges such as had cut his foot. Believing he had discovered an effective material for the manufacture of war-heads, he substituted the obsidian for the calabash points and went forth to meet his enemies. The new weapon proved more puissant than he had hoped for, and havoc was created in the ranks of his opponents. Armed with spear-heads obtained from the obsidian mountain Orito, the discoverer and his clan swept everything before them until the new material became known to all the
people. Since the time of this discovery the encounters of the islanders are characterized as more sanguinary.