Natural ultramarine in the Roman context of Volsinii (Bolsena, Italy): a multianalytical characterization

Martina Bernabale, Anna Candida Felici, Pierfrancesco Atanasio, Luca Buccini, Daniele Passeri, Marco Rossi, Paolo Binaco, Danilo Dini

Abstract

This study presents a comprehensive analysis of a blue pigment lump discovered near Volsinii (modern Bolsena, Italy), employing ED-XRF, micro-Raman spectroscopy, and XRPD techniques. The pigment was conclusively identified as natural lazurite, the primary component of lapis lazuli. ED-XRF analyses, supported by principal component analysis, revealed elemental compositions aligning closely with synthetic ultramarine pigments, yet distinct from Egyptian and Herculaneum blues. Micro-Raman spectroscopy detected characteristic S3⁻ radical peaks at 548 cm⁻¹, with additional shoulders at 585 cm⁻¹ indicative of natural origin. XRPD confirmed a predominantly lazurite crystalline structure, lacking kaolinite impurities typical of synthetic variants. The presence of such a rare and valuable pigment in a provincial Roman context suggests sophisticated material procurement and artistic practices, challenging prevailing assumptions about pigment distribution in antiquity.

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IMEKO-Metroarchaeo-2025-036.pdf

DOI

10.21014/tc26-2025.036

IMEKO TC

TC26 - Metrology for Cultural Heritage

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