Folia Historico-Naturalia Musei Matraensis - A Mátra Múzeum Természetrajzi Közleményei 14. (1989)
Könyvismertetés
- Opal can be observed as a translucent milk-white mineral or an olive-coloured green mass - From the zeolites the klinopthiloli te (Fig. 9) and the stelleri te (Fig. 8) are present in the form of small crystals (Kisnána, Domoszló, Abasár, Recsk) . Near Mátraderecske, in the Eocene andésite, somewhat different, a bit poorer paragenesis was found: here in the veins dolomite , quartz and goethite appeared. Here, as thin veins, heulandite accompanied by chalcedony could be also observed in the rock. Study of the amygdaloidal andésite of the Northern and Middle Mátra Mts. resulted in discovery of a rare association in that mountains. In the exhalition phase biotite , hematite and also the less frequent pseudobrookite tabular crystals of mm size were formed. A remarkable fact is that a frequent mineral of the pseudobrooki te associations to be found in the Carpathians, the tridimite was missing. This association may be covered by hydrothermally formed minerals like calcite , dolomite , siderite , geothite , quartz , opal , Mn-oxides and clay minerals. In the E and N Mátra Mts. zeolitic paragenesis occurs at several sites. A new collection from the classical localities and the analysis of the finds unanimously proved that the "raw" zeolites considered so far natrolite or scolcenite really are mordenite . An interesting paragenesis has been found at Mátraalmás, consisting of pyrite , calcopyrite , quartz , calcite , barite , seladonite , and harmotome . This is the first proved occurrence of this mineral in Hungary. Its elongated crystals of 1-3 mm are of pseudotethragonal tethra twins (Fig. 12) and the harmotome is bound to andésite, and is accompanied by the small tabular crystals of klinopthilolith (Fig. 13). Here the secondary goethite and Mn-oxide occur also frequently. In the N. Mátra Mts. the glauconite-seladonite formation bound to andésite has been known for a long time. We have .extended the study of this phenomenon and by applying SEM analyses we could find the reasons for the fine-type mineral associations and their appearance (Fig. 11) (Mátrakeresztes, Mátraszentimre, Parádsasvár). In the S Mátra Mts. the large scale presence of siliceous rocks filling in the fissures of andésite is important. In the veins the following minerals can be found: pyrite , marcasite , calcite , barite , quartz , opal , and mordenite . It is remarkable that the quartz (chalcedony) fs pseudomorhosa following the calcite. The aragonite 7 s star-shaped penetrating twin consisting of three crystals being already pseudomorphose is, in fact, quartz with a size of 10 cm, and is a really unique formation (Figs. 14-15 ). The colour of chalcedony appearing in the veins is influenced by hemati te , goethite , Mn-oxide and seladonite . The chalcedony of varied motifs accumulating in cavities, after proper cutting, may offer splendid agate variétés. (Gyöngyöstarján, Gyöngyösoroszi , Gyöngyössolymos) III. Minerals of quartzite versions In the Central and S Mátra Mts. the quartzites has been known from several localities. Their mineral associations are also known and here we should like to describe new data. The adular type sanidinine versions appear at several exposures. Honey-coloured anatase crystals of mm size, with pyramidical shape, could be obseved at one locality (Gyöngyössolymos-Névetelenbérc, Fig. 16). In the quartzite of Gyöngyössolymos-Asztagkő stibiconite was observed, and accordingly presence of tripuhyite is probably also present (Figs. 17-18). So, this mineral association contains the most Sb-oxide versions in Hungary. IV. Minerals of sedimentary rocks Analysis of the minerals of these formations has offered only a few surprising results. In the cavities of the Triassic limestone calcite and goethite , in the covering clay of the Visonta lignite quarry pyrite , marcasite , gypsum and quartz , and in the pebble measure of the S Mátra Mts. opal ized tree remains were found. 29
