Abstract
The occurrence of titanian-aegirines in alkaline rocks has been summarized to illustrate the extent of their stability and the nature of the substitution in these clinopyroxenes. The chemistry and substitution of Ti in aegirines is discussed with special reference to the newly observed aegirine — neptunite (Na2Fe2 2+TiSi4O12) solid solution. The available data indicate that neptunite should be included in the pyroxene mineral group as an alkali clinopyroxene.
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Ferguson, A.K. The natural occurrence of aegirine—neptunite solid solution. Contr. Mineral. and Petrol. 60, 247–253 (1977). https://doi.org/10.1007/BF01166799
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DOI: https://doi.org/10.1007/BF01166799