Dr. Nagy I. Zoltán szerk.: Fragmenta Mineralogica Et Palaentologica 4. 1973. (Budapest, 1973)
of about 60 with each other is a twinning complex within which the Albite, Carlsbad and Roc Tourné laws occur. Between the single members of the complexes grown obliquely to each other the twinning law according to (110) or (130) as well as their left forms can be determined. The Albite, Carlsbad and Roc Tourné twin members are mostly intergrown in the (010) plane ,further , however, Albite and Carlsbad twins of irregular intergrowth and of ragged contact can also be observed. The contact of the two oblique complexes is always irregular, composition plane could not be observed. At the beginning the explanation of certain intergrowths proved to be difficult. Some of the grains show the contact demonstrated in Pig. 1. In this case the section denoted by "a" seems to be the joint straight of both complexes and this would be intersection line of the composition plane and of the slide's plane. The section "a" is parallel with the (010) cleavage direction of one of the complexes but it is not parallel with the similar cleavage direction of the other complex. This would mean that in the two complexes the intergrowth plane is crystallographically not equivalent. This contradiction needed more precious investigation in the course of which the fact was proved that the section "a" is out Pig. 1. of the vertically staged complex, it lies above that plane though by several microns only. Measurement and evaluation methods The optical investigation of the sliedes made from the abovementioned rocks was performed by the Leitz-made microscopes Dialux-Pol and Ortholux-Pol and by the Leitz-made five-axial Utable .
