A monoclinic mineral, Al2 Si2 O5 (OH)4 .2H
2 O ; kaolinite-serpentine group; soft, colorless to white; commonly
tinted by impurities. (It is called halloysite in European literature.)
Formerly called hydrated halloysite, hydrohalloysite, hydrokaolin.
Source:
Dictionary of Mining, Mineral, and Related Terms