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International audience; This research is part of the PON (Programma Operativo Nazionale) SINAPSIS (SIstema NAzionale Protezione SIti Sensibili), an interdisciplinary project combining archaeological and archaeometric methods. This paper focuses on frescoes from one of the 70 funeral monuments belonging to "Porta Mediana" Necropolis, a very interesting archaeological context located in Cuma, dating back to the first half of the 3rd century BCE. The study provided detailed information on pigments and colors acquired both on untreated and treated (restored) frescoes. Portable colorimetry and chemical-mineralogical (Raman spectroscopy and X-ray powder diffraction-XRPD, respectively) analyses were performed in situ and on collected samples in order to: 1) identify pigments, raw materials and provenance, 2) point out possible color changes caused by conservative treatments and/or weathering. The identified palette is typical of the Roman period; it includes both single and mixtures of two or more pigments to obtain particular hues. Moreover, the identified raw materials, such as red and yellow ochres, green frit and Egyptian blue, clearly highlighted the choice to use raw materials from local sources. The use of expensive coloring materials also suggests that the mausoleum belonged to a family or a group of people with a high social status.

Ancient pozzolanic mortars show the high technological quality achieved by Roman construction workers, due to their ‘excellent state’ of preservation in every environment. These workers well knew that thanks to the combination of lime with specific volcanic products (pozzolana), mortar and concrete become hydraulic, allowing underwater hardening and increasing mechanical strength. The use of pozzolana in a mortar provides the underwater curing (hydraulic limes) of whatever construction with higher speed compared to carbonation processes of slaked lime. Whenever pozzolana is not available, it is substituted by ceramic fragments, which possess similar hydraulic properties. This research focuses, for the first time, on the detailed characterization of mortars coming from the Thermal Complex of Baia, which represents one of the most important archaeological sites in the Campania region. Thanks to several thermal springs, the ancient city of Baiae (Campi Flegrei) was the holiday resort of the Roman aristocracy. The former Soprintendenza Archeologia della Campania, allowed us to perform non-invasive, but representative, sampling of mortars that were characterised by multianalytical methodologies (POM, XRPD, SEM-EDS, TGA, and MIP) providing useful information on possible future activities of restoration. Results confirmed the expertise of Roman workers, who skilfully combined volcanic tuff aggregate, hydrated lime, and ceramic fragments. In particular, the typical zeolitic mineral association of phillipsite > chabazite > analcime found in the tuff aggregate pointed out their provenance from the Neapolitan Yellow Tuff related to the volcanic activity of Campi Flegrei of ca. 15 ka BP. The most relevant characteristic detected in all studied samples is the mortar hydraulicity testified by evidences such as reaction rims between pozzolana and binder, Hydraulicity Index (HI), and thermal analyses investigation. Also, composition of secondary mineralogical phases in the cementiceous matrix is particularly relevant. Distinctive is the contemporary presence of C-A-S-H gel, calcite and gypsum. C-A-S-H gel is derived from lime/ceramic fragments reaction; calcite is likely related to the partial reaction of underburned lime; and gypsum could be ascribable to the sulphation process of calcite. These secondary minerogenetic products fill pore space and enhance bonding in pumice fragments, thus contributing to long-term durability of mortars.

The topic of this study is the archaeometric characterization of mortars from Villa del Pezzolo, a Roman Villa located in Seiano (Napoli-Campania, Italy), dated between the 1st century B.C. and the 3rd century A.D. Mortars were analyzed by means of a multi-analytical approach (polarized optical microscopy, X-ray powder diffraction, scanning electron microscopy and energy-dispersed spectrometry, thermal analyses and mercury intrusion porosimetry) according to existing recommendations. Analytical results evidenced the use of local geomaterials composed of sedimentary and volcanic aggregates in the mix design and confirmed the three distinct building phases identified by archaeologists. Volcanic tuff fragments, identified in the 1st building phase can be ascribed to Campanian Ignimbrite formation, widely cropping out in the Sorrento Peninsula, as confirmed by the presence of glassy shards, partially devitrified and replaced by authigenic feldspar, a typical feature of welded grey ignimbrite lithofacies (WGI). Volcanic aggregates in samples of the 2nd and 3rd building phases show, instead, the presence of leucite-bearing volcanic scoriae and garnet crystal fragments related to Somma-Vesuvius products. Study of these mortars allowed us to: (1) understand the production technologies, (2) highlight use of materials with hydraulic behavior, such as volcanic and fictile fragments, (3) confirm the three building phases from compositional features of mortars and (4) highlight the change over time of the volcanic aggregate for mortars mix-design.

The Sabatini Volcanic District belongs to the Roman magmatic province of Central Italy, and the Tufo Giallo della Via Tiberina was one of the most voluminous pyroclastic flow-forming eruptions in this district. Post-depositional processes strongly affected this pyroclastic flow deposit leading to the crystallization of different authigenic phases (chabazite, phillipsite, feldspar). A field volcanological survey, along with a careful mineralogical characterization of a large amount of samples of the lithified facies, allowed us to reconstruct a type section primarily based on the amounts of the main authigenic phases. Chabazite always prevailed over phillipsite throughout the entire section, although in the innermost portions of the deposit, where temperatures remained high, chabazite mostly converted into a more stable phase such as an adularia-like phase. In addition to the zeolitization process, the fairly strong mechanical properties of this tuff can be also ascribed to the diffuse occurrence of microcrystalline calcite, which re-precipitated as a secondary phase after the dissolution of carbonaceous clasts.

Porosity plays a decisive role in decay processes of stones, as the pore network allows the water penetration responsible for the several physical and chemical deterioration processes affecting stone materials. In this paper two stones (with porosity from high to medium) used in Naples and Vicenza architectures have been considered to investigate the effects produced by the application of an ethyl silicate consolidant and an anti-swelling protective agent on pore space and therefore on stone durability. A deep characterization of the pore system has been carried out as considered crucial to evaluate the effectiveness of conservation treatments and their performance through time. To this purpose, petrophysical and physico-mechanical measurements have been carried out before and after aging tests, on both untreated and treated stones. Conservation treatments, strongly affecting pore size distribution and the behavior towards water absorption, do not always improve the durability of stone, especially in Neapolitan Yellow Tuff (herafter NYT) where a set of meso-macropores was totally annealed as well as a relevant portion of ultramacropores. Such treatments favor the persistence of water in NYT rock structure still after a long time, further contributing to a fast decay of this stone after aging tests. By contrast, treatments in Vicenza Stone (hereafter VS) prevailingly occlude micro- and mesopores and only slightly affect larger pores thus again favoring the flow rate during water desorption test. Moreover, the increase of the average pore radii after treatments also improves the features of this stone that accounts for almost negligible effects after accelerated aging tests.

Industrial minerals represent an important resource for the Italian economy, both in terms of exploitation and transformation, especially in those sectors for which Italy holds a leadership such as ceramics and glass. Among Italian regions Campania is one of the poorest of such kind of resources although some geological formations could be advantageously exploited. An important role is played by the deposits of sedimentary zeolites linked to the activity of different volcanic districts occurring on the Neapolitan territory such as the Campanian Ignimbrite, the most important volcanic episode of the Campi Flegrei (Southern Italy), which blankets a wide area of the Campanian region. The Campanian Ignimbrite has been thoroughly investigated from a volcanological and petrographic point of view. However, little attention was devoted to the attainment of those information useful to verify the potential of the deposit as well as the interpretation of post-depositional mineral-forming processes that have affected this deposit and have led to the formation of several facies, among which the most important are characterized by intense feldspathization (grey facies) and remarkable zeolitization (yellow facies). X-ray diffraction, X-ray fluorescence, inductively coupled plasma emission spectrometry and scanning electron microscopy methods were used to thoroughly characterize the entire set of samples collected from 31 outcrops. Data so far acquired enabled to define the role played by several parameters (i.e., temperature, alkaline and alkaline-earth cations, etc.) in influencing the zeolitization process and the consequent crystallization of phillipsite, chabazite, and analcime. Feldspathization appears to have been controlled mainly by the emplacement temperature of the deposits. The proposed genetic model involves emplacement of the pyroclastic flow in a single episode, producing a deposit with an upward-decreasing temperature gradient. In this model, the central portion had a temperature insufficient to cause significant feldspathization, and the upper portion of the formation was affected by water percolation while still hot, producing progressive zeolitization. Volcano-stratigraphical parameters suggest some constrains on the maximum temperatures affecting the central portion of WGI. Thermodynamic data on zeolites constrain the maximum temperatures of the LYT unit which likely decrease upwards in the unit up to ambient conditions in CPF.