Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 82. (Budapest 1990)

Papp, G.: A review of the multi-layer lizardite polytypes

(ii) determination of the layer sequence in materials proved to be disordered by X-ray methods; (iii) collection of reliable chemical data; (iv) detection of small amounts of multi-layer serpentine in serpentinites, etc. An advance on the fourth research field may significantly alter our ideas about multi-layer serpentines, because recent knowledge is based on the rare examples composed mainly of relative well-ordered polytypes. The investigation of the actual structure of rock-forming serpentines is in the initial phase yet. Finally, one have to call attention again to the fact that multi-layer serpentines are only polytypes of their single-layer form even if this paper discussed them separately to- a certain extent, so their knowledge and evaluation need a coherent approach. * * * Acknowledgement- The author is indebted to Dr. ISTVÁN DODONY for calling his attention to serpentine minerals and for the valuable advice and collaboration during their investigation. REFERENCES BAILEY, S. W. (1969): Polytypism of trioctahedral 1:1 layer silicates. Clays Clay Miner. 1_7: 355-371. BAILEY, S. W. (1988): X-ray diffraction identification of the polytypes of mica, serpentine, and chlorite. - Clays Clay Miner. 3_6

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