Year: 2025
Type: article
Abstract: Advancements in stone bead technology, particularly in drilling techniques, emerged during the Indus Valley (Harappan) civilization. Long-constricted cylindrical drill bits, made from a unique stone called Ernestite, were a distinctive feature of this culture. The origin of Ernestite is a mystery due to the lack of a natural analogue and an unknown manufacturing process. This study presents a mineralogical and geochemical investigation of Ernestite stones and drill bits from several Harappan and contemporaneous sites in Gujarat, India, to uncover their origin. The isotopic ratios of Sr and Nd link the drills to the Ernestites. The texture and presence of pseudo-mullite (SiO 2 > 40 wt%) with high Al-Ti-bearing hematite suggest that Ernestites are synthetic, created through a sintering process at ~ 1100°C. An abundance of sand to silt-sized detrital quartz, along with Fe-Ti-Zr-rich minerals, indicates the use of crudely powdered sandstones and laterites as raw materials, with geochemical ties to regional sources.
Source: npj Heritage Science
Authors: M. K. Mahala, Jyotiranjan S. Ray, A. K. Kanungo, G. N. S. Sree Bhuvan, A. Chatterjee, B. G. George, N. Sorcar, Y. S. Rawat, J. S. Kharakwal, S. V. Rajesh
Institutions: Physical Research Laboratory, Indian Institute of Technology Gandhinagar, Pondicherry University, Presidency University, Indian Institute of Technology Bombay, Korea Polar Research Institute, National Centre for Earth Science Studies, Archaeological Survey of India, Janardan Rai Nagar Rajasthan Vidyapeeth University, University of Kerala
Language: English
Subfield: Archeology
Field: Arts and Humanities
Domain: Social Sciences
Open Access status: hybrid
OpenAlex ID: W4416782824