Natural Stones Used in the Orsi-Marconi Palace Façade (Bologna): A Petro-Mineralogical Characterization (original) (raw)
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Periodico di Mineralogia, 2014
Ostuni Cathedral represents an outstanding example of the monumental sacred architecture spread in Apulia (southern Italy) during the Middle Ages. The church dates back to the 15 th century and combines the local Romanesque tradition with Gothic stylistic features and elements of Dalmatian, Venetian and Arabic architecture. Between 2006 and 2007, a conservative restoration was carried out on the Cathedral. The operations mainly concerned the masonry, which is built of a local stone material known as "Pietra gentile", a soft and porous calcarenite with an excellent workability and carvability. This research aims at characterizing the stone used in the monument and its state of conservation. For this goal, onsite macroscopic observations were integrated with sample analyses by means of optical microscopy, X-ray powder diffraction and scanning electron microscopy equipped with microanalysis. In this way, the petrographic classification of the used lithotype and the chemico-mineralogical characterization of its alteration products were carried out. Finally, structural diagnostics of the masonry was performed, through on-site non-destructive ultrasonic and sclerometric tests. The results presented allow evaluating, only few years after the latest restorations, the weathering kinetics and durability of the building stone, with a particular highlight on its short-term modifications. The main alterations detected, i.e. black crusts, salt crusts, oxalate patinas and discolorations, are produced by cyclic weathering or previous conservative treatments; moreover, several patterns of physical decay are observable, alveolization and differential erosion principally, which highly affect the technical performance of the stone. These data supply further information about a material that has been studied only recently in archaeometry, although very significant in Apulia from a cultural point of view.
2022 IMEKO TC-4 International Conference on Metrology for Archaeology and Cultural Heritage University of Calabria, Italy, October 19-21, 2022, 2022
This work deals with the study of sixteen samples of natural and artificial stone materials taken from the medieval Castle of Condojanni in Sant'Ilario dello Jonio (Reggio Calabria, Southern Italy). Samples were studied using different analytical methods (Polarized Light Microscopy, X-ray Powder Diffraction; X-Ray Fluorescence Spectrometry and Energy Dispersion Microanalysis by Scanning Electron Microscope) in order to characterize their chemical, mineralogical and petrographic nature. The collected data allowed us to highlight similarities and differences among the samples, confirming the archaeological data, and to hypothesize the provenance of the limestones used for the production of the lime. In addition, the characterization of the samples was helpful to propose compatible stone materials for the restoration phase of the Castle.
SEM analysis combined with the EDXRS system are performed on many types of artistic and historical assets, in order to obtain information about the materials and their deterioration, the artistic techniques, the presence of damage, etc. This work reports the results of a study carried out on samples coming from the Orsi-Marconi palace in Bologna (Italy), from the Khazneh (House of the treasury) in Petra (Jordan), and from the Holy Cross monastery of Jvari in Mtskheta (Georgia). All these buildings are made of sandstone, the peculiarity of which is the change in colour, due to the different concentration of oxides in their composition.
Construction and Building Materials, 2012
The Palazzolo Formation calcarenite, commonly known as ''Pietra di Noto'', has been widely used in the late Baroque monuments of the Val di Noto area. In this work, two different lithofacies have been identified through a minero-petrographic and physical-mechanical characterisation of the Noto stone samples. These latter have been taken out from three quarries, two of which are located near to Noto Antica (Porcari and Leone), and one next to Palazzolo Acreide (Camelio). Samples from Camelio have a white-cream colour and a higher sparry cement abundance than those from the Porcari and Leone quarries, which display a yellowish colour, a minor resistance and a more heterogeneous texture due to the presence of bioturbation (trace of fossils). The greater compactness of samples from Camelio compared to the other two is related to their higher ultrasonic velocities, better mechanical properties and reduced capability to absorb water by capillarity and total immersion which are related to the textural features. The existence of two lithofacies better explains the heterogeneity of degradation forms (chiefly consisting of differential degradation, alveolization, detachment and chromatic alteration) that can be observed on the monuments built in these stone materials. The main causes of deterioration have been related to bioturbation, as well as to the occurrence of expandable clay minerals (smectite) and to salt crystallization. The presence of bioturbation also affects the mechanical characteristics of these stones.
2015
Sardinian medieval monuments are mainly made up by volcanic rocks (pyroclastics/ignimbrites), minor granitoids and sedimentary rocks that show a more or less significant chemical-physical alteration. Mineral-petrographic features, physical properties related to petrogenetic processes, as well as manufacturing, strongly influence type and intensity of stone-decay. The granitoids show an alteration degree less than the other rock-types, due to low porosity (<10%) that does not favor an easy absorption of circulating solutions, thus avoiding the water-rock interaction and hydrolysis. In a few cases, a physical intra-crystalline decohesion, that causes a rounding of the sharp edges of ashlars, can occur. The presence of oxidation patinas and the chloritization of micas are imputable to the action of chemical alteration phenomena. The pyroclastics/ignimbritites, widely used in medieval architecture for the excellent workability, are affected by greater alteration due to the different ...
Applied Sciences
During the last restoration campaign of the Baptistery of San Giovanni in Florence (Italy), the assessment of the state of conservation of external surfaces was performed, with a multi-analytical approach, in order to support the conservation and restoration treatments. Black crusts, red staining, sulphation, and organic patinas were identified. Moreover, a complete characterization of marble cladding, bricks, and mortars was carried out. A geochemical and minero-petrographic approach was used in order to classify and assess the provenance of marbles, and define raw materials and technologies of the production for bricks and mortars. Provenances from Italy (Carrara and Lasa marbles) and from Greece (Hymettus and Pentelicum marbles) were identified and attributed to different construction phases, restoration interventions, and re-use of ancient materials. For mortars, the obtained data suggested the use of local materials and traditional technologies for the production. Overall, two ...
HISTORICAL BUILDING STONES OF THE COSENZA PROVINCE, CALABRIA (ITALY): PROPERTIES AND WEATHERING
In the Province of Cosenza, stone is the most important building material, used in the architecture of the past, both for the construction of vernacular architecture and for monumental buildings. Stones have been utilized with a structural function, principally for the construction of structural elements such as mamposteries, portals and arches, as well as with an ornamental purpose, for the realization of decorative elements. The majority of Calabrian constructions were built with natural stones quarried from the neighborhood. This study focuses on the characterization of four quarry materials: granite of San Giovanni in Fiore, Grisolia stone, calcarenite of San Lucido and sandstone of Fuscaldo. These materials belong to the northern area of Calabria, the Tyrrhenian Coast, specifically from the geological Verbicaro Unit (limestone, dolomitic limestone and calcareous breccia), from the sedimentary succession of Coastal Paola Mountains (calcarenite and sandstone) and to the central area, from the geological Unit of Sila Batholith (granite). The petrophysical and mechanical properties of these samples have been analyzed in order to determine the causes, effects, behavior and response to deterioration of these rocks. The combined use of different techniques, no destructive, micro-destructive and destructive tests, furnished information about superficial and intrinsic properties of stones. Buildings examples show weathering aspects, from low levels to high effects, and in some cases, locally an impressive deterioration. The test results provide useful information for the preservation of historical buildings and to new construction, that would benefit from a complete knowledge of these building stones.
… and Building Materials, 2012
The Palazzolo Formation calcarenite, commonly known as ''Pietra di Noto'', has been widely used in the late Baroque monuments of the Val di Noto area. In this work, two different lithofacies have been identified through a minero-petrographic and physical-mechanical characterisation of the Noto stone samples. These latter have been taken out from three quarries, two of which are located near to Noto Antica (Porcari and Leone), and one next to Palazzolo Acreide (Camelio). Samples from Camelio have a white-cream colour and a higher sparry cement abundance than those from the Porcari and Leone quarries, which display a yellowish colour, a minor resistance and a more heterogeneous texture due to the presence of bioturbation (trace of fossils). The greater compactness of samples from Camelio compared to the other two is related to their higher ultrasonic velocities, better mechanical properties and reduced capability to absorb water by capillarity and total immersion which are related to the textural features. The existence of two lithofacies better explains the heterogeneity of degradation forms (chiefly consisting of differential degradation, alveolization, detachment and chromatic alteration) that can be observed on the monuments built in these stone materials. The main causes of deterioration have been related to bioturbation, as well as to the occurrence of expandable clay minerals (smectite) and to salt crystallization. The presence of bioturbation also affects the mechanical characteristics of these stones.
This paper presents the petrographic and textural characterization of some ornamental limestones widely used in UNESCO World Heritage sites in northeastern Italy, and the assessment of the main decay factors present in the environment where they are employed. Eleven carbonate building materials have been here considered, all commonly present in the built environment of northeastern Italy: two different varieties of Vicenza Stone (Nanto and Costozza), of Verona Stone (Red and Brown Verona), of Asiago Stone (Pink and White Asiago), and of Chiampo Stone (Ondagata and Paglierino), the Istria Stone (Orsera), the Aurisina Stone, and the Botticino Stone. The Carrara marble is also considered, and used as a reference material for the determination of the grain-size distribution. Stone durability was measured by accelerated ageing tests which reproduced freeze-thaw and salt crystallization cycles, among the main causes of deterioration in the region. Petrographic and textural features of the...
Fuscaldo sandstone, commonly named as “tuff” due to its easy workability, was utilized in the past by the most important Calabrian schools of stonemasons to realize structural and ornamental elements, such as buildings, arches and portals of many Calabrian historical centers. In this work, an evaluation of sandstone deterioration of important architectural elements of the old town of Fuscaldo, situated in the Province of Cosenza (Italy), has been carried out through tests in situ and laboratory analysis. Non-destructive tests have been performed in order to assess chemical and physical-mechanical properties of the building material and its state of conservation. A preliminary architectural contextualization has been essential to evaluate principal characteristics of the architectures of Fuscaldo and to highlight the macroscopic effects of weathering. Building type analysis was obtained through a field survey and direct measurements. In particular, two architectonical elements have been investigated: the main portal of the church of Immaculate, realized during the XVIII century and the ancient entrance door of the old town, named as “Porta San Francesco”, built in 1686. The mechanical properties of sandstone have been assessed on site by means of Schmidt Hammer Hardness Test. Additional chemical and morphological SEM analyses have been performed in laboratory in order to identify anomalies in rock samples structure and the grade of weathering, as well as to compare unweathered and deteriorated samples. The aim of this paper is to combine laboratory testing of the chemical and morphological composition of weathered and unweathered samples and in-situ measurements of mechanical properties of the sandstone and its weathered parts.