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ABSTRACT The object of the present work is the archaeometric study of the mortars from the S. Niccolo archaeological site in Montieri (Tuscany--Italy). The petrographic, mineralogical and chemical characterisation of [...]

Portorois one of the most famous Italian black limestones due to its characteristic golden-yellow veins on a black background. It was used since Roman times, mainly in the city of Luni. Since the Middle Ages, its use is widespread in Genoa, and from the XVII century, it became one of the most common stones in religious buildings throughout Italy. At the end of the XIX century, its use has spread abroad, particularly in Europe and USA. It was extracted in several quarrying areas located near La Spezia, but at present, only five quarries are active. This stone, exposed to weathering, tends to bleach losing the appearance of its golden streaks that determine its aesthetic appeal. This research deals with the petrographic and chemical characterization of the Portoro macchia largavariety as well as the study of its chromatic alteration in order to define guidelines for the most suitable use of this stone and for restoration works.

Abstract: This paper focuses on the long-debated topic of the so-called calcium oxalate films: their origin and meaning but also their age and original appearance. The restoration of the main facade of the Siena Cathedral provided a unique opportunity to this end, thanks to the possibility of an extensive and detailed sampling and (as rarely happens) a sufficiently accurate historical knowledge of the construction vicissitudes. This work, mainly based on a polarising microscopy study (coupled with X-ray diffraction and SEM-EDS analyses) of over a thousand thin and ultra-thin sections of 400 microsamples, demonstrates that the current relicts of films are the result of alteration and decay of ancient treatments. In most cases, these were linseed oil-based glazings (the use of this substance is confirmed by historical documents) and pigments. Their role was essentially aesthetic; their use dates the beginning of the fourteenth century and continued at least until the eighteenth century.

Abstract The W-Mo deposit of Perda Majori (SE Sardinia) consists of a NW-SE trending quartz vein that crops out for about 500 m in the Salto di Quirra region. Hercynian low-grade metamorphic rocks, which host the orebody, largely dominate the geology of the area and are themselves intruded and contact metamorphosed by late Hercynian leucogranites and leucogranite porphyries. Field evidence supports a genetic link between the orebody and the emplacement of the leucogranites. The ore paragenesis consists chiefly of wolframite, molybdenite, scheelite, pyrite and calcopyrite, while the gangue is formed of quartz, K-feldspar, albite, topaz, micas, fuorite and calcite. The highest Th (320-420 °C) were found in coarse-grained quartz (Qz I) which also records signs of boiling. Inclusions found in wolframite, giving Th 310-330 °C and the highest recorded salinities (6-7 wt.% NaCI eq.), suggest that ore deposition closely followed the boiling.

•Mortars from 13th–16thcenturies masonries of Sienese grand buildings are analysed.•Medieval mortars were made with aerial lime binders.•Natural hydraulic binders were used since the second half of the 15thcentury.•A change of the lime stones supply sites over the centuries is established.•Sandy aggregates were derived from local Pliocene sands and sandstones.