Geologists at the University of Silesia in Poland have discovered two minerals new to science and have named them edgrewite and hydroxyledgrewite in honor of University of Maine geologist Edward Grew.
The new minerals were discovered by Evgeny Galuskin and Irina Galuskina in the Chegem caldera in the Northern Caucasus, near Mount Elbrus in the Kabardino-Balkaria Republic in Russia. The Galuskins are Russian mineralogists who have worked for more than 20 years at the University of Silesia. A caldera is a huge crater-like structure produced in very large explosive volcanic ash eruptions. Examples of calderas in the United States are found in Yellowstone and Crater Lake National Parks. When blocks of pre-existing sedimentary rocks were caught up in the Chegem caldera eruption, they were heated up to temperatures of 900 degrees Centigrade (1,650 degrees Fahrenheit). The heat turned these “xenoliths” of former sedimentary rock into calcium silicate metamorphic rocks called skarns that contain many rare minerals, including edgrewite and hydroxyledgrewite. The Galuskins have already discovered 18 minerals new to science in xenoliths of the Chegem caldera.
“The field area where the Galuskins discovered my namesake minerals is so remote that I don’t expect ever to be able to visit the locality in person,” says Ed. “But now that these minerals have been described in the scientific literature, I am hoping that mineralogists will look for edgrewite and hydroxyledgrewite, and hopefully discover other localities for them in the world.”
Edgrewite and hydroxyledgrewite were only found as tiny crystals less than 0.4 mm long and could only be identified under the microscope –they are smaller than the typical size of a period at the end of a sentence in a newspaper. Chemically, the new series ranges from edgrewite Ca9(SiO4)4F2 to hydroxyledgrewite Ca9(SiO4)4(OH)2 in which oxygen and hydrogen (“hydroxyl”) replaces fluorine in the formula. These new minerals are structurally related to the humite group of minerals. The diagram of the edgrewite crystal structure determined by Biljana Lazic and Thomas Armbruster shows its similarity to the magnesium fluorosilicate clinohumite.
Edgrewite and hydroxyledgrewite have been officially approved as new minerals by the International Mineralogical Association, and as required, a peer-reviewed scientific report of the discovery has just been published in the November-December issue of the journal American Mineralogist. The authors are Evgeny Galuskin, Irina Galuskina and 9 colleagues from Germany, Poland, Russia and Switzerland. The team includes crystallographers Biljana Lazic and Thomas Armbruster, as well as mineralogist Nick Pertsev, all of whom had collaborated with Ed on previous mineralogical studies during his career.
In the article, the authors wrote that the name edgrewite honors Ed as “a well-known scientist in the areas of mineralogy and petrology at the University of Maine,” who has “discovered or collaborated in the discovery of 10 new minerals.” The citation continues that “since his first expedition to the Antarctic from 1972 to 1974 when he wintered at Molodezhnaya Station, Ed Grew has collaborated successfully with Russian scientists.”
“I am thrilled to have two new minerals named after me,” says Ed. “It is a life-long dream come true. I have always valued my international collaborations in science, and so I was especially honored that colleagues in Europe proposed my name for the new minerals they discovered.”