The blade, cut into a point from a piece of black obsidian (volcanic glass), is fitted with a peduncle for attaching it to the weapon.
Good condition; two marginal chips.
Cf: Ancient tools, and unpublished forms (in shattered obsidian) belonging to the Polished Stone civilization of Easter Island, Dr Stephen Chauvet, Bulletin de la Société préhistorique francaise, 1935.
https://www.persee.fr/doc/bspf_0249-7638_1935_num_32_7_6134