Obsidian Reference Samples (RS) are representative obsidian specimens selected from geochemical groups defined by the chemical composition of geologic obsidian. They are used as reference materials for provenance identification of archaeological obsidian artefacts.

Obsidian Reference Samples（RS，黒曜石基準原石）とは，黒曜石原石を，地理的な原産地ではなく化学組成に基づいて区分し，各化学組成グループを代表する，黒曜石製石器の原産地判別のための基準原石を指します。