MOESM1 of Trachyte weathering in the urban built environment related to air quality

Additional file 1. Trace-element chemical composition expressed as ppm of representative samples of Euganean trachyte from the Renaissance city walls of Padua determined by LA-ICPMS, on both surface (i.e., weathering crust or patina) and host rock (inner part). The samples are divided by different types of alteration and sampling location as in Fig. 2 (SCR, Bastione Santa Croce; GAR, Torrione dell’Arena; CSN, Bastione Castelnuovo; FST, Torrione Venier)

Internal structure.

<p>μ-CT reconstructed sections of stones S1 and S2: A: lighter grey colour, outermost portions; B: darker colour, innermost portions; C: black colour, fractures within the stone; D: light grey colour, calcite filling in some of the fractures.</p

Calculi structure.

<p>SEM backscattered electron images of the microstructure of stone S3: a) outermost portion of the stone, where ovoidal structures occur; b) detail of the ovoids surrounded by a thin shrinkage rim; c) detail of the dense packing of crystals which form micron-sized spheres in some cases with a geode type structure and (on the left) acicular crystals aggregate of apatite; d) micro-fractures crossing the stone, filled by secondary calcite; e-f) micro-pores due to bacterial attack.</p

Mineralogical composition.

<p>X-ray diffraction pattern of stone S3: phase labels: Ap: apatite, Wht: whitlockite, Cal: calcite.</p

Calculus internal portion and mineral phases.

<p>SEM secondary electrons image of loose material from the internal portion of stone S3: coexisting crystals of apatite (tabular/prismatic crystals of hydroxylapatite forming radiating clusters) and whitlockite (rhombohedral crystals).</p

Calculi from Grave 188 at Al Khiday.

<p>a) geographic location of Al Khiday sites in Sudan; b) Pre-Mesolithic Grave 188; c-d) calculi <i>in situ</i>.</p