The synthesis of feldspars at temperatures between 0 �?80 � C, their ordering behaviour and twinning
| Autor: | Werner Flehmig |
|---|---|
| Rok vydání: | 1977 |
| Předmět: |
010504 meteorology & atmospheric sciences
Chemistry Potassium Nucleation chemistry.chemical_element 010502 geochemistry & geophysics Alkali metal Feldspar 01 natural sciences law.invention Crystallography Albite Geophysics Geochemistry and Petrology law visual_art visual_art.visual_art_medium Crystallization Crystal twinning Chemical composition 0105 earth and related environmental sciences |
| Zdroj: | Contributions to Mineralogy and Petrology. 65:1-9 |
| ISSN: | 1432-0967 0010-7999 |
| DOI: | 10.1007/bf00373564 |
| Popis: | Potassium feldspars, albites, plagioclases (20–38% An) and quartz were synthesized at very low temperatures by means of hydroxide gels in aqueous solutions which may be similar to the solute contents in natural environments. The formation of plagioclases in this connection is likely to be metastable. Optical and X-ray examinations of single feldspar crystals revealed the presence of monoclinic and triclinic potassium feldspars, intermediate albite, and low albite with high chemical purity in each case. Degree of ordering and chemical composition of the resulting feldspars depends on pH and alkali concentration. Higher pH and salt concentrations produced more and more ordered feldspars. In the experiments the formation of albite was restricted to pH values above 8, whereas the growth of potassium feldspars has taken place in a greater pH range between 5–10. A characteristic feature of gel grown feldspars are the nearly non-idiomorphic shapes of larger crystals and the occurrence of polysynthetic twinning probably indicating rapid crystallization after nucleation. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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