Application of Portable X-Ray Fluorescence (PXRF) for compositional analysis of metallic heritages of Ethiopia and implications
Keywords:
Part of the study is published in Amharic in the Journal of Ethiopian Church studies (No 8, 2023)Abstract
In this study data generated with Portable X-Ray Fluorescence (PXRF) through community service in one of the Ethiopian Orthodox Church (EOTC) museum is used. The PXRF was applied to determine the type, mineral content and quality of gold (karat) of heritages along with visual observations. Measurements of elemental compositions on more than 331 contemporary and antique museum items helped to know the proportions of major and minor trace elements. The hand and processional crosses in the museum indicated two or three elemental compositions of major elements (Gold (Au), Silver (Ag) and Copper (Cu); Gold and Copper; Silver and Copper; Silver and Nickel (Ni)). Minor elements include Chromium (Cr), Tungsten (W) and Titanium (Ti) and particularly observed on memorials and souvenirs (e.g., medals, pendants and watches). Minor amounts of Tungsten which can tolerate high temperatures are added as part of a jewelry practice to increase durability and toughness. The presence of Chromium indicated to avoid tarnishes on Silver made items. Some heritages are decorated with unidentified colored stones. Similar ones are seen in other Ethiopian museums. Documentation of the colored stones and associated metals in terms of (e.g. carat, color, cut, benefits) are not available. These gaps along with destructive goldsmith practices for identification of gold karats and the lack of modern visiting applications would expose the heritages for covert theft. The FDRE Mines proclamation to regulate transactions of minerals does not include specific articles about treatments and required declarations. The absence of national labs for identification, certification and proofing standards further exacerbates the challenge by making the regulatory process inept. The application PXRF is very crucial for quick feedbacks about the compositions of the heritages without damaging the physical appearance and protection of heritages in all Ethiopian museums.
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