Folia Historico-Naturalia Musei Matraensis - A Mátra Múzeum Természetrajzi Közleményei 14. (1989)
Könyvismertetés
On Minerals of the Mátra Mts. I. Sándor SZAKÁLL This study is more or less an introduction to the description of on the minerals found in geological formations in Hungary. The Mineral Collection of the Herman Ottó Museum (Miskolc) started the systematic collecting on the documentary samples of mineral associations from Hungarian localities ten years ago. As a result, by this time, the most complet collection of samples from Hungary could have been developed. An active part was played by Hungarian collectors (1012 persons) who also worked as regional chiefs for different mountaineous regions, Simultaneously with the colecting activities registration of the material was also carried out with the participation of experts from universities of Veszprém, Budapest and Miskolc. Here opportunity is taken to express our thanks for the kind help of collectors and mineralogists. The following laboratory methods were applied: X-ray powder differactrometry SEM, electron microprobe, transmission electron microprobe, thermoanalysis , and X-ray spectrometry. In the near future we attempt to publisch the results related to different mountains in Annales volumes of local museums. Because of the large amount of the material emphasis was, first of all, laid upon the separation of the mineral phases of the associatioms and their exact determination. For this reason no detailed investigation of the taxa was carried out. More detailed results will be published soon. New information offered at geological formations are summarized in a compact way, and the more important localities are given in brackets. I. Minerals coming from rhyollte versions Rhyolite versions are known only from two smaller sites of the mountains. First of all the lithophase rhyolite is rich in considerable associations. The association generally consists of quatzite crystals (1-5 mm), tridimi te in the from on thin-table mostly twin crystals of 1-2 mm (Fig. 1). Biotite is also present in the from of hexagonal table-type crystals of 1-2 mm. The secondary goethite was formed from siderite and magnetite respectively, and in certain cases beautiful pseudomorphic crystals could be observed. Especiaally at goethite pseudomorphism of pilon type, after crystallization, can be observed (after the hyperstene ?). Opal and Mn-oxids are also worth mentioning. These latter are videly scattered in forms of dendrite, globe and crust from. (Localities: Gyöngyössolymos, Kis-hegy, Lőrinci, Mulató-hegy). II. Minerals of andésite origin The most important Miocene volcanite of the site is the andésite. In the cavities situated in the SE and E regions a very characteristic association occurs. Its main feature is that following an exhalative formation a cooler hydrothermal phenomenon was present and finally secondary crystals were formed. Minerals of the exhalation phase: - tridimi te (tabular crystals of 1-3 mm of multiple penetration or they are contact twins - biotite (1-3 mm richly laminated hexagonal crystals /Figs. 2-3/), - hornblende (1-3 mm massive or colon-type elongated crystals (Figs. 4-5) - apatite (elongated colon-type crystals /rare/ Fig. 6) - anorthite (1-2 mm tabular or massive crystals /Fig. 7/). This association is, however, sometimes fully covered by a clay mineral belonging to the smectite group. Members of the hydrothermal phase are the - calcite with scaleohedric and rhombohedric shapes occuring also in spherical form - the aragoni te (known both in rough-surface, bond-type sets and also in needle-type crystals), - siderite known in its appearance in rhomboedic and spherosiderite forms, and a curst-type material as well), - the quartz is not frequent (it appears in crystal form of some mm, and chalcedony form, respectively) 28
