A set of five manuscripts written by Sister Lucia between 1941 and 1944 were under study. Among them is the one that contains the description of the third part of the Secret of Fatima also known as the Third Secret of Fatima. In this work, a characterization of the paper and the ink used in these documents was achieved using micro-X-ray fluorescence spectrometry. Quantitative results were obtained for P, K, Ca, Fe, Cu and Zn, revealing different paper composition and Zn in the inks. 20 elemental maps confirmed that Zn was present in the five documents ink and that the manuscript revealing the Third Secret of Fatima contained no erasures or alteration attempts to the original manuscript. (C) 2017 Elsevier B.V. All rights reserved.