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The aim of this work is to present preliminary mineralogical aspects of an unusual found approximately 50 Km at north of Belo Horizonte, Minas Gerais-Brazil, buried in a partially eroded colluvial fan. The rock debris was dispersed over an area of approximately 10,000 m2. Some field evidences point out to a meteoritic origin for the material. Two hundred fragments, about 200 Kg, were recovered. It shows conspicuous meteoritic shapes, remaglyptes and black to colored fusion crusts. At least two mineralogical assemblages may be separate. The main assemblage represents over than 90% of total rock comprising coarse to fine crystallized minerals characteristics of Ca-Al-rich-inclusions of chondrite meteorites. The main mineral phases are corundum and spinel. Corundum is the most abundant mineral and it's often coarse crystallized, light pink colored to colorless, with a composition close to 100% of Al2O3. Spinel is dark to light brown, red and blue coloured euhedric crystals with almost pure end-member composition. Its commonly show a triangular pattern of crystallization resembling the Wittmanstatten figures. The only identified silicates are of the gehlenite-mellitite group, but anomalous Zr-rich and Al-depleted minerals compositions couldn't be related to any known minerals phases. Grossite is coarse crystallized and was surely identified, but the electron microprobe analyses of several crystals of Ca-Al oxides show a standard deviation up to 20%. Polymetallic nodules with internal structures of high crystallinity were found as inclusions in corundum-spinel matrix or isolated with dimensions ranging from spherules <1mm to oval shaped nodules >10cm. The most common shapes are spheroidal and globular. Seldom well-marked meteoritic shapes nodules with small remaglyptes and black fusion crust were found. The surfaces of the nodules are often light gray-bluish to golden colored and nearly always stainless. Oxidation is from weak to moderate and it is present in <5% of the samples. Strong magnetism is characteristic of most samples and almost all of them show fine to coarse crystals of cubic symmetry. Very few nodules don't have magnetic properties, perhaps due the weathering or lack of iron in the bulk composition. Its chemical composition is extremely variable but the metal content is up to 90%. Several alloys, sulfides and phosphides were identified. At least one dozen of unknown minerals and alloys were observed. Only kamacite [(a(Fe,Ni)], two iron silicides [xifengite(Fe5Si3) and gupeiite (Fe3Si)] and spharelite were confirmed by XRD and electron microprobe. Particles of Cu-Ni-Sn, Fe-Ni-Cu, Fe-Ni-Cu-Sn, Fe-Si-Ti, Fe-Si-Cr, Fe-Si-Ti-Al alloys are quite common in all the analyzed nodules. Minor amounts of W, Pb, Zr were determined. The Ca-Al-Mg rock and the polymetallic nodules represent either, a refractory mineralogy, and melted metal formed under extreme reduced conditions and do not seem to have an affinity to any known meteorite class.
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