Obsidian as Grave Furniture: The Case of Secondary Burial Jars at the Ulilang Bundok Site, Batangas, Philippines

Leee Anthony M. Neri

Obsidian is a natural glass produced by the extrusive action of volcanoes. This is formed by the rapid cooling of magma, which prevents crystallization and yields a fine-grained texture. Its conchoidal fracture and amenability to knapping made it highly prized for tools and ornaments in ancient times. Obsidian has been one of the most widely exchanged raw materials in the past. In the Philippines during the Neolithic period, obsidian was widespread, and its distribution may intersect with Austronesian mobility toward the Pacific. In the Metal Age, the secondary burial culture across various islands was incorporated into elaborate mortuary contexts. Some burial jars show intricate anthropomorphic, geometric, and zoomorphic designs, including exotic materials. Secondary burial jars found at the Ulilang Bundok Site in Batangas also exhibited unique grave furniture. Disarticulated human skeletal remains, along with beads, shells, polished stone, nephrite adzes, and obsidian flakes, were prominent. The use of obsidian in Batangas as a mortuary offering is very unique across the islands. Over time, the functional use of obsidian as a stone tool “declined,” and its value became increasingly tied to grave furniture and ceremonial significance. The advent of metal likely influenced an “inflation” in the obsidian market, prompting a shift from practical tool use to ritual offerings intended to preserve its materiality. Crucially, these cultural hypotheses have yet to be satisfactorily tested. This will further develop a multidisciplinary framework linking artifact morphology, mortuary rites, and broader socioeconomic changes during the transition from the Neolithic to the Metal Age.