Identification of red, purple, and black pigment used in rock art from Sangkulirang sites, East Kalimantan using Raman spectroscopy
Evi Maryanti (a*), Yana Maolana Syah (b), Pindi Setiawan (c), Grandprix. T.M. Kadja (d,e), Ismunandar (d)

a) Department of Chemistry, Universitas Bengkulu, Bengkulu, Indonesia, 38371
*evi.maryanti[at]unib.ac.id
b) Division of Organic Chemistry, Institut Teknologi Bandung, Bandung, Indonesia, 40132
c) Division of Visual Communication and Multimedia, Institut Teknologi Bandung, Bandung, Indonesia, 40132
d) Division of Inorganic and Physical Chemistry, Institut Teknologi Bandung, Bandung, Indonesia, 40132
e) Research Center for Nanosciences and Nanotechnology, Institut Teknologi Bandung, Bandung, Indonesia, 40132

Abstract

Four pictorial panels from sites in the Sangkulirang area, East Kalimantan, which have unique prehistoric rock arts, have been studied using Raman spectroscopy. X-ray Fluorescence (XRF), Scanning Electron Microscopy, and Energy-dispersive X-ray spectrometry (SEM-EDS) were used as auxiliary techniques. The identification results show that the mineral hematite (alpha-Fe2O3) is used as a red, purple, and black pigment in the rock arts at the Jufri Cave, Lubang Suud, and Lubang Stefanus. However, apart from hematite, amorphous carbon was also identified in the black pigment material from the Bloyot Cave. Differences in Fe concentration, elemental composition, crystallinity, and particle size of hematite cause discrepancies in pigment hues in rock arts at the Sangkulirang sites. The presence of hematite as the main component of black pigment in rock art is new and has been reported for the first time.

Keywords: Rock art, hematite, Raman spectroscopy, Sangkulirang sites

Topic: CHEMISTRY AND MATERIAL SCIENCES