Iki Island obsidian discriminant groups: IK-1 (Kuki and Indoji), IK-2 (Tsubo), and IK-3 (Hakozaki). Oki-Dogo Island obsidian discriminant groups: OD-1 (Kumi), OD-2.1 (Kamo), OD-2.2 (Kamo), OD-3.1 (Sai), and OD-3.2 (Sai). Parentheses indicate the obsidian sources.