Browsing by Author "Oliveira, Isaac Gomes de"
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- Gemological analysis of ruby origins: a case studyPublication . Oliveira, Isaac Gomes de; Cardoso, Jessica de Sousa; Franco, Julia; Santos, Breno Ravielly dos; Silva, Suely Andrade da; Santos, Lucilene; Mattos, Irani Clezar; Neri, Tereza Falcão de OliveiraABSTRACT: Gemstones are substances of natural, artificial or synthetic origin, which due to their hardness, rarity, uniqueness, diaphaneity and beauty are used as adornments. In the market, ruby is the second most expensive type of gemstone. Depending on its size, it can exceed the value of the diamond, besides being the most valuable colored gem in the market. It is a variety of the mineral corundum, just like sapphire, and it is a form of crystallized alumina (Al2O3) and the responsible for its red color is chromium. There are deposits in many different places around the world, being common the practice of speculating the origin of the ruby based on the shade of red. Provenance strongly impacts the commercial value of the gem. Several faceted rubies were donated to the Federal University of Ceará. This project aims to discover from what regions (countries) the donated rubies are coming, using gemological characteristics. To establish the origin of the specimen collection, the following methods and equipment were used: bibliographic research about rubies characteristics, refractometer to measure refractive indexes, dichroscope for pleochroism analysis, ultraviolet lamp (UV) for determination of fluorescence, and especially the gemological (stereoscopic) microscope to study the types of inclusions in transparent to translucent rubies. Using the methods cited, it was possible to produce, successfully, the gemological characterization of the specimens and deduce, based on strong evidence, what was the geographic origin of the studied specimens. Through microscopy it was deduced that all the faceted stones are natural and the whole collection include stones from the following countries: Burma, Thailand, Pakistan, Sri Lanka and Tanzania. Results are gathered systematizing bibliographic data and analytical results in order to identify the country of origin of the rubies.