The published values of the indices of refraction of ascharite, 2MgO · B2O3 · H2O, are shown to be incorrect. The correct values, with new chemical analyses, and x-ray powder photographs, show the identity of szaibelyite, ascharite, camsellite, and β-ascharite. A compilation and discussion of the properties and analyses of these minerals is presented.

The isomorphous series szaibelyite-sussexite is discussed with a compilation of properties and analyses, and the variation curve plotted. A similar treatment is given for the fluoborites. The indices of refraction for the masnesium borate minerals with corrections are compiled.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not have access to this content, please speak to your institutional administrator if you feel you should have access.