Non-Destructive Multi-Analytical Approach to Study the Pigments of Wall Painting Fragments Reused in Mortars from the Archaeological Site of Pompeii (Italy)

Domenico Miriello,Nicola Ruggieri,Alessandra Pecci,Massimo Osanna,Alberta Martellone,Andrea Bloise,Raffaella De Luca,Rossella Pace,Gino Crisci,Bruno De Nigris

doi:10.3390/min8040134

Abstract

During the excavations carried out in Via di Mercurio (Regio VI, 9, 3) in Pompeii, in 2015, some red, green, black, and brown wall painting fragments were found in the preparatory layer of an ancient pavement which was probably built after the 62 AD earthquake. These fragments, derived from the rubble, were used as coarse aggregate to prepare the mortar for building the pavement. The wall painting fragments are exceptionally well preserved, which is an uncommon occurrence in the city of Pompeii. However, as they were enclosed in the mortar, the wall painting fragments were protected from the high temperatures (probably ranging between 180 °C and 380 °C) produced by the eruption in 79 AD. The pigmented outer surface of each sample was analyzed using a non-destructive multi-analytical approach, by combining spectrophotometric colorimetry and portable X-ray fluorescence with micro-Raman spectroscopy. The compositional characterization of the samples revealed the presence of cuprorivaite, goethite, and celadonite in the green pigments; hematite in the red pigments; goethite in the brown pigment; and charcoal in the black pigment. These data probably provide us with the most “faithful picture” of the various red, green, black, and brown pigments used in Pompeii prior to the 79 AD eruption.

Highlights

The archaeological site of Pompeii is located on a plateau produced by prehistoric lava flows, on the southern flank of Vesuvius [1] in Southern Italy.Minerals 2018, 8, 134; doi:10.3390/min8040134 www.mdpi.com/journal/mineralsThe area has been inhabited since the Middle Neolithic period
We successfully applied a non-destructive multi-analytical approach to analyze exceptionally preserved wall painting fragments which had been reused as recycled coarse aggregate to make the preparatory layer of an ancient Pompeian pavement
The compositional results obtained are very important, because they provided us with insight into the pigments used in Pompeian wall paintings, which had not undergone mineralogical and chromatic changes due to the increase in temperature during the 79 AD eruption

Summary

Introduction

The archaeological site of Pompeii is located on a plateau produced by prehistoric lava flows, on the southern flank of Vesuvius [1] in Southern Italy.Minerals 2018, 8, 134; doi:10.3390/min8040134 www.mdpi.com/journal/mineralsThe area has been inhabited since the Middle Neolithic period. In the late 7th to early 6th century. The city was later conquered by the Samnites and in the 4th century BC passed under Roman jurisdiction. The 62 AD earthquake destroyed most of the city which was reconstructed, but Pompeii was once again completely destroyed and buried under the volcanic eruption of 79 AD [2,3,4]. For this reason, Pompeii offers a snapshot of Roman life in the 1st century AD as it has remained undisturbed since it was buried on

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