The term ‘marble’ in eighteenth-century encyclopaedic literature: from colourful and exclusive to grainy and popular

This article reports on findings concerning the use and understanding of marble in the eighteenth century, as uncovered by a team of geologists and conservators at the Department of Engineering Technology at the Technical University of Munich. While researching a group of marble objects in Bayreuth in order to devise suitable conservation methods, it became apparent that the eighteenth-century understanding of ‘marble’ was different to how we define the stone today. This earlier definition of marble was based on colour, pattern and the ability to shine when polished. However, by the end of the eighteenth century, there was a shift to a focus on the different grain sizes of the stones, while the previously defining quality of colour became less important. Such developments advanced towards the recognition of limestone and marble as two different types, enabling the distinction between sedimentary limestone and its metamorphic product marble to be drawn in the first half of the nineteenth century. At the same time, the exploration of local sources caused the exclusivity of marble to dwindle. Once a building and decorative material for the elite, it now became more widely available. Marble was still the material of sovereigns - proudly presented as locally found - but it simultaneously became accessible to a wider market for household utensils or collectors’ items. This is demonstrated through the exploration of a range of German sources, including encyclopaedias and lexicons with their inherent aim of accumulating the universal knowledge of their time, a ‘marble’ compendium, and a description of the prison and workhouse in St Georgen in Bayreuth, which had marble works on its premises.