Color Research and Application, Vol.41, No.3, 241-245, 2016
The colour of the granite that built the city of SAo Paulo, Brazil
The city of SAo Paulo, until the 1900s, was restricted to a small central nucleus, also called the Historic Triangle, where there is a concentration of the oldest monuments and buildings of the city. They are built with a number of ornamental stones, but one of these predominates: Itaquera Granite. Currently, it is not quarried, but its exploitation dated from 1888. It was replaced by Gray Maua Granite after the 1940s, partly because the Itaquera quarry was becoming exhausted and partly due to better technological characteristics of Maua Granite. There are numerous examples of cultural heritage monuments and buildings made with Itaquera Granite in SAo Paulo's city. The examples selected for this study are: Saint Anthony's Church, The Girl and the Calf, Nostalgia, the Law School of the University of SAo Paulo, After the Bath and Amerindian Hunter. The purpose of this article is to characterize Itaquera Granite according to its colorimetric aspects and its colour variation. Colorimetric changes in the stone can be caused by many factors, such as cleaning methods, deposition of atmospheric pollutants, biological colonization, leaching of bronze, dissolution and reprecipitation of mortar, or even by natural causes such as the oxidation or alteration of minerals present in the stone. Measuring the change in colour can be useful for monitoring the development of natural changes, analyzing the effectiveness of treatments, and monitoring the degree of biological colonization in the monuments. In the long run, these data may aid in the treatment and restoration of these monuments. (c) 2015 Wiley Periodicals, Inc. Col Res Appl 41, 241-245, 2016