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Licensed Unlicensed Requires Authentication Published by De Gruyter March 31, 2015

Pressure-induced hydration in zeolite tetranatrolite

  • Yongjae Lee EMAIL logo , Joseph A. Hriljac , John B. Parise and Thomas Vogt
From the journal American Mineralogist


The tetranatrolite-paranatrolite transformation has remained a key problem in understanding the paragenesis of zeolites in the natrolite family. It is accepted that when paranatrolite, approximate formula Na16-xCaxAl16+xSi24-xO80·24H2O, is removed from an aqueous environment and exposed to the atmosphere, it loses water and transforms to tetranatrolite, Na16-xCaxAl16+xSi24-xO80·nH2O (n ≤ 24). Here we show that this transformation is not only reversible, but that tetranatrolite exhibits two sequential pressure-induced hydrations leading first to paranatrolite and then to a superhydrated tetranatrolite above 0.2 and 3.0 Gpa, respectively. We have previously reported similar behavior for the corresponding system with an ordered Si/Al distribution, i.e., natrolite itself, however the ordered version of paranatrolite exists over a much smaller pressure range. The pressure-induced transformations of natrolite and tetranatrolite thus further supports the supposition that paranatrolite is a distinct mineral species, with a pressure-stability field dependent upon composition.

Received: 2004-11-8
Accepted: 2005-6-17
Published Online: 2015-3-31
Published in Print: 2006-2-1

© 2015 by Walter de Gruyter Berlin/Boston

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