# “Hungarian Mine Green”, a Semi‐Natural Copper Pigment from Banská Bystrica Region (Slovakia) ‐ Analytical Evidence and Laboratory Replication

## TL;DR

This study investigates the historical 'Hungarian mine green' pigment, analyzing its composition and replicating it in the lab to understand its use in 16th-17th century artworks.

## Contribution

The paper provides the first detailed analytical and experimental replication of the 'Hungarian mine green' pigment from Slovakia.

## Key findings

- Posnjakite and malachite were most frequently detected in historical artworks.
- Brochantite and malachite were dominant in mine site rock samples.
- Laboratory experiments showed brochantite transformed into posnjakite and then malachite.

## Abstract

A comprehensive approach is taken to investigate the “Hungarian mine green” pigment, including a historical overview, analysis of the pigment on artworks, and its laboratory replication. It is known that in the past, the pigment is collected in wooden reservoirs in which copper (Cu) compounds precipitated from drainage water during copper mining at Špania Dolina–Piesky and Ľubietová deposits, Slovakia. Microsamples of four polychrome wooden sculptures from the 16th‐17th centuries are examined. Posnjakite (Cu4SO4(OH)6·H2O) and malachite (Cu2(CO3)(OH)2) are most frequently detected by X‐ray powder microdiffraction. In rock samples from the mine site, brochantite (Cu4SO4(OH)6) and malachite are dominant, and in recent precipitates, only langite (Cu4SO4(OH)6·2H2O) is detected, remained in contact with leaking water. In the laboratory, the pigment is prepared by gradually enriching the starting CuSO4·5H2O solution with NaHCO3 in two series of experiments. The initial concentration of the reactants reflected the ratio of Cu2+: HCO3
− = 1:1 found in the mine waters at the site, from which langite crystallizes. However, langite does not formed, while brochantite gradually transformed into posnjakite and subsequently malachite. The co‐occurrence of basic copper sulfates and carbonates and the characteristic grain morphology proved to be the main indicators of the pigment in artworks.

Hungarian mine green, a pigment precipitated from drainage water containing basic copper sulfates and carbonates, represented an important product for painters with the peak of its production in the 16th and 17th centuries in the Banská Bystrica region (Slovakia). Morphological and compositional fingerprints have been described based on microanalysis of Late Gothic artworks and pigment's replication in the laboratory.© 2025 WILEY‐VCH GmbH