Szakáll Sándor - Jánosi Melinda: Minerals of Hungary (Topographia Mineralogica Hungariae 4. Miskolc, 1996)

THE BÖRZSÖNY MOUNTAINS Most of the Börzsöny consists of Miocene andésite, where large hornblende and augite crystals, formed during the main crystallisation stage, can be seen in many of the quarries. In some quarries, the andésite contains inclusions of different origins, which have their own distinctive contact-metamorphic mineral assemblage (almandine, grossular, corundum, andalusite). Hydrothermal and autopneumatolitic mineral assemblages found in cavities and vesicles within the andésites can be of different types (as in andésites of the other mountains). These may include rock-forming minerals (mainly plagioclase, magnetite and hornblende), oxides (hematite and tridymite) or carbonates (calcite, siderite and aragonite), or they may occur together with zeolites (analcime, chabazite, stellerite, epistilbite, and phillipsite; Fig. 44). The chief locality for thinly tabular hematite crystals is Huszár Hill, at Bernecebaráti, whereas that of carbonate and zeolite cavities is Csák Hill quarry at Szob. Traces of molybdenite of hydrothermal origin are found in some of the quarries in this area. Fig. 44 EPISTILBITE (0.6 mm xl) Szob