title: Natural or Artificial? Multi-Analytical Study of a Scagliola from Estoi Palace Simulating Imperial Red Porphyry.
abstract: In this paper the characterization of a gypsum plaster sample from the end of the 19th century simulating imperial red porphyry using a multi-analytical approach is presented and discussed. The results of X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TGA-DTA), physical and mechanical properties are summarized. In order to have further insight into the microstructure, polarized light microscopy (PLM), scanning electron microscopy coupled with energy dispersive X-ray spectrometer (SEM-EDS), and micro Raman spectroscopy analyzes were also made. They helped to clarify the main issues raised by the other complementary analytical techniques and allowed the establishment of interrelations between the different properties, providing important information about the materials, the skills, and the technological development involved in the art of imitating noble stones with gypsum pastes. This study also contributes to our knowledge concerning the preservation of these types of elements that are important in the context of European decorative arts and rarely reported in the literature.
authors.affiliation: 1Buildings Department,National Laboratory for Civil Engineering,Av. do Brasil,101,1700-066 Lisbon,Portugal.
authors.forename: Maria Teresa
authors.identifier: 0000-0001-9402-0501
authors.initials: MT
authors.lastname: Freire
authors.affiliation: 2Materials Department,National Laboratory for Civil Engineering,Av. do Brasil,101,1700-066 Lisbon,Portugal.
authors.forename: António
authors.initials: A
authors.lastname: Santos Silva
authors.affiliation: 1Buildings Department,National Laboratory for Civil Engineering,Av. do Brasil,101,1700-066 Lisbon,Portugal.
authors.forename: Maria do Rosário
authors.initials: MD
authors.lastname: Veiga
authors.affiliation: 3CERIS-ICIST,Department of Civil Engineering,Architecture and Georresources,Instituto Superior Técnico,Universidade de Lisboa,Av. Rovisco Pais,1049-001 Lisbon,Portugal.
authors.forename: Jorge de
authors.initials: J
authors.lastname: Brito
authors.affiliation: 4Department of Analytical Microscopy of Building Materials,Bremen Institute for Materials Testing,Paul-Feller-Straße 1,28199 Bremen,Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Schlütter
keywords: 
                 scagliola
              ; gypsum technology; microscopy; multi-analytical characterization; multiphase gypsum plasters