The Source Materials for Lime Production in the Monte Pisano Area (NW Tuscany, Italy)

In the Monte Pisano area (north-western Tuscany, Italy) several limestones outcrop and some of them are carbonate-rich rocks that were used for air-hardening lime or hydraulic lime production. Since Roman times, carbonate rocks outcropping in the Monte Pisano area have been used for that purpose. Monte Pisano is a mountainous system of modest size that is part of the Tuscan Apennine, located in the north-western part of Tuscany, and it separates the two cities of Pisa and Lucca. As an obvious consequence of the presence of good source rocks useful for the production of lime, in the surroundings of Monte Pisano there was a great use of carbonate rocks for the production of aerial lime and hydraulic lime. In fact, the monumental buildings in the Middle Ages were built making extensive use of binding materials obtained by firing rocks belonging to formations of the Tuscan metamorphic sequence: the Monte Pisano marble and the Selciferous Limestone. Several famous monuments in Pisa’s Miracle Square and in Lucca’s historical centre were built by using air-hardening lime and hydraulic lime obtained by firing these rocks. The aim of this work is to characterize samples from the Monte Pisano quarries, where the aforementioned carbonate-rich stones were quarried to produce airhardening lime and hydraulic lime, by mean of chemical, mineralogical and petrographic studies and by determining their physical and mechanical properties. These same properties will also be determined on handmade mortar samples made up of self-produced binders and normalised sand to evaluate the best uses, and the optimum time and temperature of stone firing

LIBS analysis to define the alteration processes on the surface of ancient stones: the case study of Romanesque medieval monuments (Italy)

Weathering and bio-deterioration processes frequently affect the chromatic aspect of the stones used in the monuments. The surface alteration involves both physical modifications (e.g., increase of porosity) and chemical-mineralogical transformations of the rock, with formation of new secondary phases and deposition of the organic substances and inorganic solid phases (amorphous or crystalline particles). This research aims to study the surface films of stones (i.e., basalts, pyroclastic rocks, limestone, marbles) used in some historical-cultural relevant Sardinian Romanesque churches (XI-XIV sec.) using LIBS and XRD analysis. These latter, together with petrographic analysis by polarized light microscopy in thin section, are useful to reconstruct the micro-stratigraphic aspects of different film levels. The results highlight three different cases: i) chromatic alteration of the stone surface, ii) chemical-mineralogical alteration of stone with formation of coatings similar to the stone substrate, iii) chemical-mineralogical processes with the formation on the surface of secondary phases not related to the substrate, with the presence of Ca-oxalate (i.e. weddelite, whevellite). The presence of the Ca-oxalates, as noted in literature, is a testimony of application of organic substances on the surfaces themselves, with aesthetic purposes, to standardize or improve the color of the stone, or conservative, to limit the negative effects of weathering

Synopsis of a Treasure. A Transdisciplinary Study of Medieval Gold Workings Biographies

The article aims to show how a transdisciplinary approach can contribute to a better understanding of the composite biography of a precious object. The study focuses on the Cintola del Duomo (Museum of the Opera del Duomo, Pisa), one of the most famous objects in the history of goldsmithing, both for its exceptional manufacturing quality and for its devotional value. For a long time, the Cintola was considered a fragment of a long garland – decorated with precious stones, enamel, and silver plates – that was displayed on the façade of the Cathedral on certain days of the liturgical calendar. Detailed historical studies suggested that the garland was lost in the early 1300s, while the object now in the museum is more likely to be a reconstruction, decorated with ancient and modern gems. In situ diagnostic campaigns were carried out on the garland using portable Raman spectroscopy (i-Raman, B&W Tek) and portable X-Ray fluorescnece (XRF) (Elio, Bruker) to reveal the identity of the gems and enamels preliminarily studied by gemmological analysis. The combination of analytical techniques made it possible to better outline the complex history of the artefacts. The analysis provided information on the identity of the gems, proposing an interesting question about their possible relationship with the crown of Henry VII of Luxembourg (in the same museum). The study includes aspects related to the materiality of the objects, revealing the socio-cultural context in which the object was produced and supporting its recontextualisation in the museum as a symbolic representation of the past

Evaluation of potsherds features using hyperspectral maps generated by μ-LIBS scanner

The micro-laser induced breakdown spectroscopy (µ-LIBS) technique allows performing fast elemental analyses, without sample preparation and thus making it specifically useful in the analysis of the composition of ancient potsherd. The µ-LIBS instrument is equipped with a microscope and a scanning system allowing to realize small craters (about Ø = 25 µm) in order to obtain detailed hyperspectral surfaces maps (up to a maximum size of one square centimeter). The data are processed by Self-Organizing Maps (SOMs) method to visualize in 2D representations allowing significant information on the technological features of ceramic samples.The micro-laser induced breakdown spectroscopy (µ-LIBS) technique allows performing fast elemental analyses, without sample preparation and thus making it specifically useful in the analysis of the composition of ancient potsherd. The µ-LIBS instrument is equipped with a microscope and a scanning system allowing to realize small craters (about Ø = 25 µm) in order to obtain detailed hyperspectral surfaces maps (up to a maximum size of one square centimeter). The data are processed by Self-Organizing Maps (SOMs) method to visualize in 2D representations allowing significant information on the technological features of ceramic samples

PROTEUS: an immersive tool for exploring the world of cultural heritage across space and time scales

AbstractIn the field of digital humanities, it is increasingly necessary to develop and validate virtual reality tools that are capable of combining various scientific data in a virtualized context providing also access and user friendly consultation of online repositories. This paper reports the main aspects of the implementation of a virtual reality tool integrated with an online repository for storing 3D models, metadata and chemical analyses related to different sectors of digital humanities. The virtual reality software, developed for the Oculus Quest 2 hardware, is called PROTEUS and allows for seamless transition from the macroscopic world of digital humanities to the microscopic world of molecular sciences. The paper illustrates, by means of some case studies, the performances of this innovative tool that permits the researcher to understand and manipulate objects, to test hypotheses and to seek meaningful results, visualising the metadata while changing the parameters of the simulation in a dynamic and interactive way. This represents also a significant step forward in the democratisation of science, thanks to an user-friendly and immersive access to advanced scientific algorithms, which allow the natural perception of structural and topological features of the underlying molecular and supra-molecular systems. Graphical Abstrac

Shedding light on the composition and degradation mechanism of dyes in historical ink's collection (19th-20th century)

Man has always used writing to be able to communicate, express, and disseminate his thoughts. In time, many different coloured extracts of plant and animal origin have been used to produce inks; after the development of synthetic chemistry, artificial and synthetic dyes started to be widely exploited. The end of the 19th century marked great technological and industrial innovations in commercial production of artists' materials. To reveal ink formulations and build a database of red inks by different producers, we developed a multi-analytical approach and investigated a collection of writing inks produced in France in the late 19th - early 20th century. The materials used as binders, additives, dyes, and pigments have been investigated by high performance liquid chromatography coupled with diode array and tandem mass spectrometric detectors (HPLC-DAD-MS2), in situ derivatisation pyrolysis coupled with gas chromatography-mass spectrometry (Py(HMDS)-GC/MS), surface enhanced Raman (SERS, TLC-SERS) and X-Ray Fluorescence spectroscopies. Several dyes and pigments were detected, showing that the French ink's formulations of the early days of synthetic dye industry were based on rhodamine B and 6G, eosin Y, rose Bengal and methyl or crystal violet. Instead, as binder and additives only gum Arabic and shellac resin have been identified, respectively. Mass spectrometry also allowed us to detect possible by-products of the synthesis of ink's dyes and even early degradation products, that can be used for ink identification in historical writings and drawings. Our studies can pave the way to investigate inks in historical samples by introducing ultra-sensitive chromatographic and mass spectrometric methods in the array of analytical tools available to the chemist

Mineralogical, petrographic and physical-mechanical study of Roman construction materials from the Maritime Theatre of Hadrian's Villa (Rome, Italy)

This paper presents the study of various Roman materials used in the construction of the Maritime Theatre, one of the main buildings in the Hadrian’s Villa complex, a designated UNESCO World Heritage Site located in Tivoli (Rome, Italy), dating to the first half of the II century A.D. The plaster layers (arriccio and intonachino) and overlying original Roman paintings that form the concave wall of the portico as well as some bedding mortars of the pyramidal stone elements (i.e. cubilia) of the circular masonry have been studied in particular. In addition, the acid volcanic rocks of the cubilia have been investigated, aiming to understand their state of alteration and geological origin. By mineralogical-petrographic microscopy (OM), diffractometry (XRPD), Raman spectroscopy, Point Load Tests (PLT), helium pycnometry, and particle size analysis, the composition and granulometric distribution of the aggregate, type and characteristics of the binder, and various physical-mechanical properties (density, porosity, water absorption, imbibition and saturation indices, mechanical resistance) of mortars and stones were defined. In addition, through digital image analysis of thin sections, the binder/aggregate ratio and some geometric characteristics of the aggregates (e.g. circularity) were determined. The research aims to improve the knowledge of the constructive technologies of the Maritime Theatre through the analysis of its materials

Coupling of electron and vibrational spectroscopy with false colour imaging for the investigation of natural dyes in historical fabrics (15th-18th centuries)

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Micro-chemical evaluation of ancient potsherds by μ-LIBS scanning on thin section negatives

In the study of ancient pottery, thin section analysis represents the basic approach to study mineralogical and petrografic features in order to obtain preliminary information about the production technology and origin of archaeological ceramics. However, even if thin section analysis allows investigating the textural and structural characteristics of potteries, peculiar features related to clay paste and temper composition, as well as provenance issues, can be detailed addressed only by quantitative mineralogical and chemical studies. In the realization of thin sections, a negative face is always produced, similar to the thin section itself; these remains can be used for additional analyses, such as high spatial resolution micro-chemical studies using, for example, a micro-laser induced breakdown spectroscopy (LIBS) scanner. LIBS is a spectroscopic technique that, exploiting the laser radiation, is able to bring into the plasma state micrometric portions of the sample, and to analyse its content through the study of the optical emission of the plasma itself. Unlike other techniques, LIBS can detect and quantify also light elements such as aluminium and magnesium. Images produced by the micro-LIBS instrument show the spatial distribution of the chemical elements within a portion of the sample, which may have dimensions from a few hundred microns up to several centimeters. The combination of these images with algorithms derived from image processing techniques may return interesting information and supporting data to in-depth investigate pottery components detected by optical microscopy observations. In this work, we present the results of an experimental study performed on thin-section negatives with different grain size, surface treatments and aggregates, coming from some Neolithic Italian sites, exploring the potential of the LIBS method in micro-chemical studies of ancient potsherds