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Rare Minerals from Larsemann Hills Image 2
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Rare Minerals from Larsemann Hills (Image 2)

June 29, 2010
Rare Minerals from Larsemann Hills (Image 2) Boralsilite, which consists of boron, aluminum and silicon (whence the name), forms twinned prisms such as those shown in this photomicrograph that was taken with polars crossed. Under these lighting conditions, the twinned prisms appear banded. During the 2003-2004 Antarctic research season, Chris Carson of Geosciences Australia (Australia's leading geoscience research and information agency), and Edward Grew of the Department of Earth Sciences at the University of Maine, discovered nine new localities for this mineral. Originally found in 1988 and named for the composition boron-aluminum-silicon, boralsilite has only been found in one other location worldwide--Rogaland, Norway. The boralsilite from Antarctica was found at nine localities in 2003-2004. It forms white fibrous or finely columnar bundles of prisms up to a centimeter long. In contrast to most new minerals discovered nowadays, Larsemann's boralsilite can be appreciated without a microscope. The Larsemann Hills are unique for the variety of phosphorus and boron minerals, some of which are found in spectacular specimens, and others of which are not found elsewhere. Three of the nine phosphate minerals found during the 2003-2004 season are new to science: stornesite (yttrium), tassieite and chopinite. [This research was supported by National Science Foundation grant OPP 02-28842, "Boron in Antarctica granulite-facies rocks: under what conditions is boron retained in the middle crust?"] (Date of Image: samples collected during austral summer 2003-2004; photomicrographs taken in 2004-2005) [One of four related images. See Next Image.]