This is a 'preproof' accepted article for Mineralogical Magazine. This version may be subject to change during the production process. DOI: 10.1180/mgm.2021.58 Microlite-group minerals: tracers of complex post-magmatic evolution in beryl-columbite granitic pegmatites, Maršíkov District, Bohemian Massif, Czech Republic Štěpán Chládek 1* , Pavel Uher 2 , Milan Novák 3 , Peter Bačík 2 , Tomáš Opletal 4 1 Department of Geological Engineering, Faculty of Mining and Geology, VŠB – Technical University of Ostrava, 17. listopadu 15, 708 33 Poruba-Ostrava, Czech Republic 2 Department of Mineralogy, Petrology and Economic Geology, Faculty of Natural Sciences, Comenius University, Ilkovičova 6, 842 15 Bratislava, Slovakia 3 Department of Geological Sciences, Masaryk University, Kotlářská 2, Brno 611 37, Czech Republic 4 Department of Analytical Chemistry, Palacký University, 17. listopadu 12, Olomouc 771 46, Czech Republic * Author for correspondence: Štěpán Chládek. Email: st.chladek@seznam.cz Abstract Microlite-group minerals occur as common replacement products after primary and secondary columbite-group minerals (CGM) in albitized blocky K-feldspar and in coarse-grained,