Chemical-physical diagnostics propaedeutic to the conservative restoration of the Cippo Funerario of Quinto Cornelio Procliano

This paper describes some diagnostic analyses on a funus cippus, in precious white marble, located close to an ancient Roman consular road. Even if in good conservative conditions, it is almost completely covered by a black patina; so, a conservative intervention is planned, that will be directed by one of the authors, thanks to the financial support of the Cornelia Antiqua Association and the project's approval by Dr. Roberta Pardi of the Superintendence of Rome. The use of funerary cippus dates back to the Bronze Age. They were extensively used by Etruscans, both with figurative and symbolic contents, and by Romans in the republican period as an indication of burial or "in memory" of the deceased. Even if recycled materials such as broken columns, damaged pillars and quarry waste were used, only affluent families could afford a funus cippus. The simplest cippus are rectangular or trapezoidal stone blocks but richest ones include finely worked stones, in the shape of a pinecone or similar, with great use of archaic symbology. The absence of artistic interest is always compensated by the inscription, with the precise indication of the name of the deceased and his family, in some cases the only one reference available, as in the case of study; so, also the simplest cippus are heritage works to be preserved. During a first inspection, fragments of marble that had fallen due to exfoliation were collected and the points of detachment were identified; some samples of the inconsistent patina covering the cippus were also taken. A diagnostic steps was finally planned including on-site and in-lab analyses: a) measurement of the surface temperature and humidity by systematic sampling, b) colour measurements of the original marble in the exfoliatiated areas, c) macro photography for the identification of inconsistent areas, fractures, and possible recognition, by experts, of plant and animal species already evidenced by a simple visual analysis, d) a solutions, obtained as an extract of the taken patina (UNI-BBCC EN 16085: 2012) will be used for the analysis of soluble salts by Ionic Chromatography (Li, NH4, K, Na, Rb, Zn, Mn, Mg, Ca, Sr, Ba, F, Cl, Br, NO2, NO3, IO3, PO4, SO4, Acetate, Oxalate) following norms (UNI-BBCC EN 16455: 2014); e) on the same solution, pH, Redox potential and conductivity will be measured; f) measured by means of UV-Visible spectrophotometry, indexes of colour, organic substances and turbidity, g) preparation of shiny sections for observation and dimensional analysis of the thickness of the patinas with optical microscopy and electron microscopy (SEM) and elemental composition by EDS, h) statistical analysis of the results to highlight further anomalies due to degradation. Those diagnostics aims to identify of the degradation causes (UNI-BBCC 11182:2006) and then to guide the operations of cleaning, sterilization, consolidation and application of compatible protective agents.