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

presence in cavities of a lot of octahedral fluorite crystals a few millimeters in size. Fig. 35 GALENA (8 cm sp) Fig. 36 STIBNITE (9 cm sp) Mátraszentimre Mátraszentimre In the Miocene andésites of the Mátra a number of different hydrothermal, and autopneumatolitic mineral assemblages were encountered. These associations may be divided into three groups: the first group consists of rock-forming minerals deposited on the walls of the cavities; in the second group the cavities are filled largely with varieties of quartz and opal, and with carbonate minerals. The carbonates, in particular, calcite, aragonite and siderite, abound in the quarry at Kisnána and in the andésite at Csákány-kő Hill near Recsk. The hyalite, coloured green by nontronite and celadonite, is the most common form of opal and is usually associated with chalcedony. The third group con-