Prékopa Ágnes (szerk.): Ars Decorativa 30. (Budapest, 2016)

Kornélia HAJTÓ: Zsolnay Pyrogranite: Tradition and Fact

technology of ceramics, and successfully put his knowledge of chemistry into practice to improve the company’s products. Much of his experimental work was directed at enhancing the qualities of architectural ceramics, particularly their weather resistance. The company produced a ceramic material under the trade name Pyrogranite in 1890. It was developed specifically for use in exterior facings, ornaments and art works.

Pyrogranite ornaments adorn the building of the Budapest Museum of Applied Arts. Material analysis has found that the originals differ from reproductions made at various times since. First of all, the base colour varies across a wide range of shades from deep red to off-white. The grain size and colour of the tempering material

mixed with the clay also displays considerable variation. Consequently, we cannot give a narrow technical definition of Pyrogranite. It is widely defined in the literature as a frost resistant and very hard ceramic product (the expression ‘granite hardness’ frequently being applied) made of fireclay with added chamotte and fired to high density at 1200 °C. Laboratory analysis, however, has found that Pyrogranite does not fit this description in terms of either hardness or density. Tests carried out on items from a wide range of buildings (Museum of Applied Arts, St Ladislaus’ Church in Kőbánya, Parliament, Divatcsarnok Department Store, Palace Hotel, Párizsi Udvar) have clearly found their bodies to be porous and much less hard than dense fired products such as

2. Roof ornaments of the Museum of Applied Arts. On the left is a presumed original with red ceramic, on the right is a later reproduction with white ceramic, slightly lower and wider in shape. The colour glazes are also strikingly different. Photo by Kornélia Hajtó

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