| | Book (edition) | Hig-h and low quartz IN THE MAGMA mag-ma •• Tridymite Calcite and woUastonite Action of peridotite... pressure, at all temperatures up to 870" C. tridymite between 870° and 1470° C. and cristobalite from...which ensure free movement of the molecules, both tridymite and cristobalite transform into quartz when the...unfavourable to it. Thus one can understand why tridymite and cristobalite are often found point at 1713°...unstable forms." sarily ; A. Lacroix claims that tridymite was formed, in the lavas Pelee, by crystallization | | | Book (edition) | The geological thermometer High and low quartz Tridymite ... Calcite and wollastonite Action of peridotite...pressure, at all temperatures up to 870° C.; tridymite between 870° and 1470° C.; and cristobalite from...which ensure free movement of the molecules, both tridymite and cristobalite transform into quartz when the...unfavourable to it. Thus one can understand why tridymite and cristobalite are often found in lavas, but...writes that:" The presence of cristobalite or tridymite in a rock does not necessarily imply that at the |
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