Further Observations on the Morphology of Chrysotile and Halloysite1

Thomas F. Bates and Joseph J. Comer
The Pennsylvania State University, University Park, Pennsylvania
1 Contribution no. 57-57 from the College of Mineral Industries, The Pennsylvania State University.

Abstract: Electron microscope studies of chrysotile show that tubes are present in bulk specimens and that these tubes commonly have fuzzy, amorphous-looking material on both the inside and outside. Similar material is associated with synthetic chrysotile and has been noted previously in halloysite specimens. The existence of such material between and within the tubes, together with apparent irregularities in size, shape and packing of tubes, explains the apparent discrepancy between the measured density of bulk samples and the calculated density of a hypothetical sample consisting of close-packed, regular, hollow capillaries.

Replicas of fractured surfaces of halloysite (2H2O) from various localities reveal that the particles occur as curved to flat laths commonly possessing “hexagonal” terminations and surface features indicative of a higher degree of crystallinity than tubes of halloysite (4H2O).

It is suggested that a complete morphological series from plates through laths to tubes exists both in platy to fibrous serpentine and in kaolinite to halloysite (4H2O). In each series a number of structural varieties are to be expected between the morphologically distinct “end members.”

Clays and Clay Minerals; 1957 v. 6; no. 1; p. 237-248; DOI: 10.1346/CCMN.1957.0060118
© 1957, The Clay Minerals Society
Clay Minerals Society (www.clays.org)