Traces of stone working are an integral part of natural stone objects and artefacts of historical value. Each preserved trace does not only carry a value in determining the type of tool used, but also provides information about the historic stonemason’s work process and technology. For this reason, it is desirable to assess the restoration method’s influence on the change in surface topography. The effect of restoration interventions was investigated on five stone artefacts, three of ‘opuka’, one of sandstone and one of limestone, four of which showed historic working traces. For this purpose, selected restoration methods—chemical, mechanical and laser—were used. The examined artefacts were accurately photogrammetrically captured before and after the restoration interventions in order to assess and evaluate changes in the degree of preservation of the traces. Fine results using common tools were achieved in terms of geometric quality, level of detail and the documentation’s predictive power. The models’ geometric accuracy is in the single tenths of mm, as well as the matching of the two datasets (before and after).

The aim of the contribution is introduce the role of the geologist in the process of the restoration of monuments ashlars masonry. Within the frame of our project, we participate on the reconstruction of battlements of the castle Kost, which were built predominantly from sandstones. These stones undergo to weathering processes and so they are damaged. Therefore, it has been necessary to restore and even change some blockstones. In cooperation with the experts from other branches, especially restorers and preservationists, the building blocks suitable for exchange were selected and the new replacement rock material was chosen. As it is obvious from the process of this reconstruction, the participation of geologists is indispensable.

When investigating historical building stones, we often encounter an issue concerning the original material provenance identification. Addressing this issue is usually rather complicated due to the unavailability of samples to conduct a petrographic analysis that itself often cannot fully identify the site of acquisition. It is therefore imperative to focus on non-destructive research methods applicable in the field. Great emphasis is placed on interdisciplinarity with experts from a variety of fields contributing to the achievement of relevant results. The reflectance spectroscopy method in the near- and mid-infrared spectral range (1000–2500 nm), a simple and effective method to be applied in situ, is used for non-destructive identification of stone provenance. A unique spectral reflectance curve representing the reflectance in percentages versus the wavelength can be defined for each material. Consequently, the curve can be compared with spectra in the pre-prepared library in order to find the one best corresponding to the investigated curve to identify the material. The applied traceology methods are used to determine the approximate age of the stone elements to specify the achieved results, and not least, they are compared with the results of archival and art history research. Within our research, these methods were applied during the investigation of historical stone artefacts and masonry in St. Vitus Cathedral, located in Prague, Czech Republic. The achieved results corroborate a high potential of the selected methods and approaches.

The surface of building stone on historic buildings often bears the original traces of craftsmanship processing. These are an integral part of the visual appearance of the monument and thus its value, which needs to be protected. For studying and identifying traces and subsequent reconstruction of stonemason's tools, we use the methods of traceology and mechanoscopy. Using modern imaging techniques, we can identify the stonemason's tool used, reconstruct the shape of its blade, and determine how it was used. The obtained results can be used in the process of monument care, especially in the process of preparation and implementation of restoration interventions on the objects, but they are also useful for completing the historical context of the monument. Our research is focused on the systematic study of the surface topography of the stone monuments in Prague. The obtained results were systematically divided according to individual historical period. As a model example of the use of the above-mentioned methods and approaches, we present the topography of stone elements and the development of stonemason's craft in Gothic Prague. The development of the stonemason's craft within one city in a given period can be documented on selected examples arranged chronologically in succession.

In 2015 we participated in an ashlar masonry plinth restoration of St. Anna church in the village Vižňov. The plinth is built up from sandstones, which were probably quarried in the surroundings of the church. The sandstone blocks had undergone weathering processes and some of them were strongly damaged. Therefore, the complete exchange of strongly destroyed blocks was necessary and thus the task of choosing a substitute material arose. First of all, a detailed survey of the stone's initial state was completed and then the stone plinth was described from a geological, structural and historical perspective. For the purposes of the reconstruction it was necessary to find a matching local alternative rock or a comparable one from another site. For this reason a geological survey was made to identify and document possible historic quarries from which the stone for the construction of the church plinth could be taken.