This archaeometric study was focused on 28 grey to dark-grey lava artifacts found in Ustica Island (Southern Tyrrhenian Sea, Italy) and referable to different grinding tools: saddle querns, rotary Morgantina-type millstones, rotary hand-mills and one small mortar. Mineralogy, petrography and bulk rock geochemical analyses emphasized that most of the grinding artifacts belonged to the Na-Alkaline series of Ustica, mainly basalts, hawaiites and mugearites. Nevertheless, some millstone samples did not match major and trace elements of Ustica lavas, in particular, one high-TiO₂ Na-Alkaline basalt from Pantelleria Island, some tholeiitic/transitional basalts from the Iblei Mountains and one Calcalkaline basaltic andesite, most likely from the Aeolian Archipelago. The Hellenistic–Roman re-colonisation of Ustica Island, after ca. one millennium of nearly complete abandonment, was testified by the import of the non-local Morgantina-type rotary millstones, very widespread in the Mediterranean area from 4th–3rd century BC. This import of millstones represented, for the Ustica inhabitants, a real breakthrough for developing a local production of grinding artifacts on the basis of the new rotary technique which was much more efficient than that of the archaic saddle querns, largely used in the Middle Bronze Age. The results are also discussed in the framework of the overall volcanic millstone trade in the Mediterranean area and the different milling technology in antiquity.

This study is addressed at the cultural heritage of the UNESCO historical centre of Urbino (Italy) through the focus on a very peculiar building and ornamental carbonate porous (spongy) stone also found in the opus quadratum Roman dry walls. For these rocks, the mathematician and historian Bernardino Baldi (16th century AD) and the mineralogist Francesco Rodolico (middle of the 20th century AD) introduced, respectively, the popular terms of Tufo spugnoso or Pietra Spugna. Physical observations and stable isotope data (δ¹³C and δ¹⁸O) of these rocks allowed, for the first time, their classification as calcareous tufas, thus contributing to the valorization of the stone heritage of the city. This carbonate lithotype was formed by the chemical precipitation of CaCO₃, driven by the CO₂ degassing of supersaturated calcium-bicarbonate-rich waters, coupled with the passive encrustations of organic material in continental environments. Radiocarbon analyses dated these stones mostly between 9100 and 4700 yr. BP when a maximum growth of these carbonate continental deposits occurred in Mediterranean regions and northern Europe, i.e., during the Holocene Atlantic climatic optimum. Work is still in progress on a perched springline of calcareous tufas found along the Metauro Valley (a few km from Urbino), being good candidates for provenance, at least for those blocks exploited by the Romans and successively reused in the architectural framework of Urbino.

A macroscopic lithological study and physical (hardness, size, weight) investigations, coupled with laser-induced breakdown spectroscopy (LIBS) and X-ray fluorescence (XRF) chemical analyses of three egg- and one pear-shaped polished black stones, exposed in the library of the child home of the famous poet Giacomo Leopardi, at Recanati (Italy), were carried out. They are characterized by different sizes: two with the same weight of 16.9 kg and the two smaller ones of 5.6 kg each, corresponding to multiples of standard roman weights (drachma and scrupulum). These features and the presence of some grooves on the rock artefacts, probably for grappling hooks, suggest an original use as counterweight for the four black stones herein classified as amphibole-bearing serpentinites whose lithologies are far away from Recanati (probably coming from geological outcrops in Tuscany). The four serpentinite stones closely match with the so-called Lapis Aequipondus used in antiquity by the Romans as counterweights. Due to the presence of lead rings or iron hooks in these stones, Lapis Aequipondus were also used for martyrdoms during the persecution of Christians in the Roman period, attached to the necks of martyrs that were then thrown in the wells or attached to the ankles of hanging bodies. This is the reason why these stones are also known as Lapis Martyrum, venerated with the relative martyrs, in several churches of Rome. The four black stones investigated probably arrived at Recanati from Rome after the middle of the 19th century. In the past, Christians also called Lapis Martyrum the “devil’s stones” (Lapis Diaboli). This could also be the reason for the popular belief that black stones cannot be touched by people, except those of the Leopardi dynasty. This work contributes to the cultural heritage of Leopardi’s child home, as the four black stones had never been investigated.

Roman to Modern times (19th century) brick samples from monuments, walls and other masonry buildings of the historic centre of Urbino were investigated through a multidisciplinary approach, including mineralogy and texture (thin section and XRPD), chemistry (major-trace elements), physical–mechanical properties and thermoluminescence (TL) dating, coupled with the historic literature data. TL mostly confirms the building periods of the architectural structures where the bricks were sampled, also emphasising for the Cathedral a building period that lasted more than three centuries. The supply areas of the raw materials seem to have always been the same through time, very close to the city to the West and Northwest, represented by the deposits deriving from the weathering of the Marnoso-Arenacea Formation, which was able to give both clays and sands (temper) for the bricks. Some historic documents of the second half of the 15th century reporting an act of sale of a person living in the western areas surrounding Urbino with a commitment to providing several thousand of bricks to the Cathedral factory, seem to confirm the geological constraints. The firing temperature should have been reached at least 850–900°C, as indicated by the presence of new phases such as gehlenite and clinopyroxene in almost all the investigated samples. Nevertheless, the failure to achieve complete thermodynamic conditions for both wide inhomogeneities in grainsize and composition of the raw materials and the lack of temperature control during firing, mostly gave rise to incomplete calcite breakdown. The absence of standardisation of the pyrotechnological processes probably led to the large variability of the physical–mechanical features even for bricks of the same building period. Uniaxial Compressive Strength of the investigated historic bricks, however, falls within the range of present-day full-bricks, and a general improvement of the brick quality from Roman to Modern times was highlighted, as well as a progressive refinement in preparation techniques before firing. The brick material culture of Urbino continues seamlessly, after the investigated periods, until the second half of the 20th century, testified by the presence of the brick factory of the Fornace Volponi , just outside the historic centre of the city.