Abstract
Recent work on the pyrope-grossular and almandine grossular solid solution series has shown that at concentrations of Ca up to 15mol.% the garnets show negative excess volumes and negative excess free energies of mixing. It has been suggested that this results from a change in structure caused by Ca ordering. This note describes a preliminary X-ray study of such a garnet and concludes that there is a structural change, possibly to space group I 213, caused by Ca substitution and that further work must be done to see if this is caused by ordering.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Cressey, C., Schmid, R., Wood, B.J.: Thermodynamic Properties of Almandine-Grossular Garnet Solid Solutions. Contrib. Mineral. Petrol. 67, 397 (1978)
Hazen, R.M., Finger, L.W.: Crystal Structures and Compressibilities of Pyrope and Grossular to 60 kbar. Am. Mineral. 63, 297 (1978)
Meagher, E.P.: The Crystal Structures of Pyrope and Grossularite at Elevated Temperatures. Am. Mineral. 60, 218 (1975)
Newton, R.C., Charlu, T.V., Kleppa, O.J.: Thermochemistry of High Pressure Garnets and Clinopyroxenes in the System CaO-MgO-Al2O3-SiO2. Geochim. Cosmochim. Acta 41, 369 (1977)
Novak, G.A., Gibbs, G.V.: The Crystal Chemistry of the Silicate Garnets. Am. Mineral. 56, 791 (1971)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Dempsey, M.J. Evidence for structural changes in garnet caused by calcium substitution. Contr. Mineral. and Petrol. 71, 281–282 (1980). https://doi.org/10.1007/BF00371669
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00371669