Serpentine Minerals from Veins in Serpentinite Rocks

N. Morandi and G. Felice
Istituto di Mineralogia e Petrografia dell'Università di Bologna, Italy

Summary: Crystal-chemical analyses of the serpentine polymorphs, sampled from macroscopic veins in the serpentinite rocks from Sasso della Mantesca and Sasso di S. Zanobi, are reported. The samples were examined by X-ray diffraction, thermal analysis (TG and DTG), scanning and transmission electron microscopy, IR absorption spectroscopy, microprobe, and chemical tests.

The results show: chrysotile 2Orc1 in tubular fibrils placed perpendicularly to walls of iso-oriented ‘lenticular veins’; and polygonal serpentine formed by flat layers of lizardite 2H and/or 1T, arranged as an outer shell of a central core of chrysotile 2Mc1 fibres; this type of serpentine with high crystallinity and unusual morphological development is included in ‘green veins’, which show variable Al, Fe, and Mg contents.

A genetic mechanism correlating the petrographic observations with the mineralogical results is discussed.

Mineralogical Magazine; March 1979 v. 43; no. 325; p. 135-140; DOI: 10.1180/minmag.1979.043.325.13
© 1979, The Mineralogical Society
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