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Pavle Tancic, Geological Institute of Serbia (Serbia and Montenegro)
Maja Poznanovic, Geological Institute of Serbia (Serbia and Montenegro)
Slobodanka Sudar, Geological Institute of Serbia (Serbia and Montenegro)
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At the Vranovac locality (Boranja Mt., Serbia) ludwigite was found in association with chlorite and magnetite, and investigated with the XRD and chemical analysis. It has the calculated formula: (Mg1.769Fe2+0.257Mn0.019)2.045(Fe3+0.942Al0.077Cr0.003Ti0.002)1.024B0.945O5; and crystallographic parameters: a0=9.238(3)Å; b0=12.301(4)Å; c0=3.039(1)Å; and V0=345.4(2)Å3. Therefore, it is mainly of the Mg-Fe3+ type close to the end-member with substituted Fe2+ of about 13 mol.%, Al3+ of about 8 mol.%, and with minor Mn, Cr and Ti. According to its chemical composition, i.e. substitution of Fe2+ for magnesium, the temperature of its crystallization was estimated to about 600 °C. Discovered ludwigite is an indicator of the boron-bearing Mg-Fe skarn at this locality.
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