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

with somewhat smaller (several cms long) crystals of quartz and orthoclase (Fig. 56), sometimes with tiny (a few mm long) but pretty crystals of albite, epidote, apatite, tourmaline, clinochlore, and muscovite. Fig. 58 SPHALERITE (14 cm sp) Pátka Hydrothermal processes produced a variety of mineral assemblages. Veins, several meters thick, of quartz, barite, and fluorite (Fig. 57) have been discovered, and these are sometimes linked to zinc-leadcopper ore formations. Pyrite, sphalerite, galena, and chalcopyrite are predominant (Fig. 58). As a result of oxidation near the surface of these orebodies a secondary mineral assemblage (cerussite, pyromorphite, malachite, azurite, and cinnabar) appears. During the 1950's some of the ores and fluorite veins were mined on an industrial scale. Most important of these were the mines at Szűzvár Mill and on Kőrakás Hill near Pátka and the fluorite quarry North of Pákozd. Traces of molybdenite are found all over the mountains, but the most significant