TATIANA DIAS MENEZESMatioliítaTATIANA DIAS MENEZES
“Birth!? Daniel Atencio exclaimed in an e-mail with this heading, sent on November 02, 2010, to communicate – as he explained in the ensuing text – “the birth of my twelfth daughter, carlosbarbosaíta, who has joined chernikovita, coutinhoíta, lindbergita, matioliíta, menezesita, ruifrancoíta, footemineíta, guimarãesita, bendadaíta, brumadoíta and manganoeudialita.” A professor at the Geosciences Institute of the University of São Paulo (USP), Atencio had just received a message from the International Mineralogical Association, approving his request to register the new mineral, the 54th mineral discovered in Brazil and unregistered by any other country. New mineral species, referred to as mineral type, are found aggregated to gemstones, minerals with commercial value, such as the topaz and the tourmaline, commonly found in the State of Minas Gerais. However, only two gemstones, chrysoberyl and brazilianita, had been initially registered in the country.
New minerals have unusual chemical compositions or atomic arrangements, initially without any commercial applications. They are frequently found in igneous rocks, called pegmatites, formed during the last stages of crystallization of the magma inside the Earth. The first phases of a magma’s cooling process results in simpler and more homogeneous rocks and minerals. As the magma crystallizes, the rarer chemical elements form a sort of residual soup. This residual liquid then solidifies and originates pegmatites that are often rich in phosphate. In Brazil, the eastern region of the State of Minas Gerais is one of the richest regions in pegmatite – and, therefore, in new mineral species. Four new mineral species of minerals were found in Divino das Laranjeiras, one of the municipalities in this region, among which are atencioita, a brown mineral described by Russia?s Nikita Chukanov, and brazilianita, a gemstone with greenish yellow crystals. Ten new minerals were found in the neighboring region of Galileia.
Since December 2006, when a mineral called carlosbarbosaíta came out of a stone quarry located next to a soccer field in the municipality of Jaguaraçu, it has followed a route that illustrates how the discovery of new mineral species is a combination of patience, friendship and close collaboration among academic and non-academic specialists. Luiz Menezes, a mining engineer and collector whose line of business is the selling of minerals, collected specimens of what seemed to him to be a new material. He conducted initial analyses by using an electronic microscope from the Federal University of Minas Gerais. As he was unable to proceed with his research, he sent a sample of the material to USP. Atencio examined the material with X-rays, and confirmed that it was indeed a new species of mineral. Atencio, however, was also unable to proceed with the research, because the crystals, which measured 50 x 10 x 5 millionths of a millimeter, were too small and therefore too difficult to analyze. For the same reason, for four years researchers from USP/São Carlos, Canada, Russia, and the United States, who had joined the research studies, made some progress until finally, in April 2009, Mark Cooper, from the University of Manitoba, in Canada, was able to get X-ray equipment to conclude the analyses. He was thus able to elucidate the mineral?s atomic structure, whose crystals form long needles rich in uranium oxide and niobium.
At the request of Menezes, Atencio chose to name the new mineral in honor of Carlos do Prado Barbosa, a chemical engineer and collector of minerals, who had passed away in 2003. Barbosa had participated in the identification of bahianita, recognized as a new mineral in 1978, and in the identification of minasgeraisita, recognized as a new mineral in 1986. Geologists who are still alive can also be honored in this way, even though, like the biologists, they cannot give their own name to the mineral species they themselves discover.
Menezesita, a mineral rich in barium, zirconium and magnesium, was given this name in recognition of the work done by Menezes, who lives in the capital city of Belo Horizonte and always sends interesting things to geologists. Recognized in 2005 and published in 2008, menezesita?s atomic structure is similar to that of a compound that had been synthesized in 2002 to fight the Aids-causing virus.
The light of minerals
Coutinhoíta, a mineral whose yellowish color resembles that of sulphur, is a uranium and thorium silicate that Atencio and Paulo Anselmo Matioli, a geographer who had graduated from the Catholic University of Santos, brought from the region of Galileia, State of Minas Gerais. Coutinhoíta is another example of the pioneers’ gratitude – in this case, the gratitude goes to Moacyr Vianna Coutinho, a professor at USP who disseminated the use of polarizing microscopy in the late 1950’s, after he had come back from the University of California at Berkeley, United States. Polarizing microscopy indicates the deviation of light to show the atomic structures, which facilitates the identification of minerals in Brazil. As a result, Coutinho participated in the naming of nine of the 16 new Brazilian minerals identified in the last eight years, including carlosbarbosaíta. “I help wherever I can,” says the 86-year old Coutinho, who still goes to his office at the Geosciences Institute of USP.
“Coutinho has a fantastic eye for microscopes and a remarkable talent to draw crystals and the optical arrangements of minerals,” says Atencio, showing the drawings that illustrated an article from 1999, in which he and his colleagues described hainita, a mineral found in the town of Poços de Caldas, on the border of the states of Minas Gerais and São Paulo. In another corner of the room stands a metal shelf with samples of silex that Atencio had found at the age of 10 at a construction site near his house in the town of São Bernardo do Campo. This episode later defined his decision to become a geologist.
Two a year
Many new minerals are found in a single place only, but a reddish-colored mineral, with the virtually unpronounceable name of tupersuatsiaíta, had already been identified in Greenland and in Namibia before 2005, when Atencio, Coutinho and Silvio Vlach, also of USP, reported what they had found in Poços de Caldas. Sometimes, the official description of a new mineral special conciliates concurrent discoveries. This was the case of bendadaita, a mineral with elongated, greenish crystals found in Portugal, Brazil, Chile, Morocco and Italy that geologists from seven countries – Austria, Germany, France, Russia, Australia, Brazil and the United States – describe in the June 2010 issue of Mineralogical Magazine.
“Sometimes it is easier to collaborate with researchers from Russia and Germany than from Brazil,” says Atencio. He says that the main reason is the lack of mineral identification specialists – there are less than a dozen of such experts, while Italy has about 200 and Russia has many more. Nonetheless, the number of new mineral species identified originally in Brazil has been growing. Up to 1959, there were only 19 mineral species considered valid, most of which had been described only by foreigners. From 1959 to 2000, the new minerals committee of the International Mineralogical Association recognized 18 new species, an average of a 0.43 per year, and, in the last eight years, it had identified another 16, thus increasing the average to two a year. According to Atencio, Brazil is among the countries where more new minerals are currently discovered, almost as frequently as in the United States. Russia is where new minerals are found most frequently.
The discoveries do not proliferate for reasons other than the lack of specialists. At the stone quarries, a common procedure is to treat the gemstones with commercial value by submitting them to an acid bath to remove impurities, including possible novelties. Parties interested in new minerals sometimes come across them before the gemstones are submitted to the acid baths. Another problem is the transformation of the space. Atencio says that in 1991 he and Reiner Neumann – the first student that he had advised – Antonio Silva and Yvonne Mascarenhas, his collaborators at the Physics Institute of USP, São Carlos since the 1980’s, had described rare uranium minerals found in the town of Perus, in the municipal region of São Paulo State. “There were probably a lot more,” he says, “but the Rodoanel ring road buried everything.”
The project
New minerals in Brazil – crystal-chemical characterization and synthesis (nº 2009/09125-5); Type Regular Research Awards; Coordinator Daniel Atencio – IG/USP; Investment R$ 79,750.75
