S0885-7156(96) 01203-l] It has been pointed out to us that an error occurs in the EPMA data presented in the above article. In this study we used EPMA data for two purposes: first, qualitatively, to determine whether elements other than Na, Al, and Si were present; and, second, for quantitative determination of the ratios of major elements. Qualitative analysis of the emitted X radiation failed to demonstrate excitations for elements other than Na, Al, and Si. We then performed controlled

more »

... ation of the natroiite sample under the electron beam and analyzed the residue to determine the relative ratios of Na:Al:Si. We recognize now that the residue did not have metal ratios consistent with natroiite due to losses during dehydration, and therefore we withdraw the quantitative EPMA data presented. Qualitative EPMA and characterization of the sample by other methods, including the X-ray diffraction data at the heart of the article, enjoy our full confidence. The authors would like to express their thanks to Dr. Alexander Holzel for pointing out this error.