Tracht and habit of synthetic minerals grown under hydrothermal conditions
Franke, Walter A.
European Journal of Mineralogy Volume 1 Number 4 (1989), p. 557 - 566
published: Aug 31, 1989
manuscript accepted: Nov 1, 1989
manuscript received: Nov 1, 1989
ArtNo. ESP147050104006, Price: 29.00 €
Abstract The results of investigations into the hydrothermal growth of several minerals are reviewed with respect to the influence of temperature and other growth conditions on the morphology of the crystals. For non-cubic silicates and oxides with increasing temperature more faces are entering the growth form, simultaneously an isometric habit is approached. Supersaturation and extraneous substances are without influence on the morphology. A bias of the pH value of the fluid phase on the habit of alkali feldspars is stated. For carbonates a temperature dependence of the morphology was observed merely as an exception for strontianite at high supersaturations. In all other cases of carbonate growth the influence of supersaturation was found to be prevailing. The rank of observed growth faces of nearly all prooved minerals was in good agreement to theoretical considerations based on symmetry and structure, like Donnay-Harker rule or PBC calculations.