Determining the mineralogical properties of Gua Sagu ancient pottery using X-Ray Diffraction and portable Raman spectrometer

This paper highlights the mineralogical properties of earthenware pottery shards excavated from Gua Sagu archaeological site in Kuantan, Pahang. Six earthenware pottery shards from different trenches and spits were selected for mineralogical analysis. For provenance study, soil samples collected from the site during the 1990-1991 excavations and clay samples obtained during the 2022 fieldwork from Sungai Batu, the nearest river to Gua Sagu were included in this study. Selected pottery samples, as well as the clay and soil samples, were analysed by means of X-Ray Diffraction (XRD) and portable Raman Spectrometry (pRS). The analyses reveal that the mineral compositions of the Gua Sagu pottery consist mainly of quartz, hematite muscovite, albite, microcline and kaolin. The same minerals were identified in clay samples from Sungai Batu while gypsum and hydroxyapatite were observed in soil samples from Gua Sagu. It can be concluded that the Gua Sagu pottery was composed of high-grade clay, and was sand-tempered and fired in an uneven atmosphere at low temperatures presumably around 650 °C or less. However, the Gua Sagu pottery was not made by using clay sourced from Sungai Batu. The pottery may have been a trade item brought in from elsewhere to be used for cooking or storage. A lesson from this study is that the portable Raman spectrometer is a fast and easy-to-use device for the spectroscopic characterisation of ancient pottery.