Stishovite: Thermal Dependence of the Crystal Habit

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Science  15 May 1964:
Vol. 144, Issue 3620, pp. 833-835
DOI: 10.1126/science.144.3620.833


The crystal habit of stishovite changes with the temperature of crystallization at a pressure of about 120 kb. Below 600 ° C it is bipyramidal; between 600 ° and 900 ° C it is granular; and above 900 ° C it is acicular. This temperature dependence of the crystal habit of stishovite may constitute a highpressure geological thermometer which could indicate limiting values for the peak temperatures that prevailed at craters of meteoritic origin in highly siliceous rocks. It suggests that natural acicular stishovite from the rim sandstone at Meteor Crater, Arizona, crystallized at temperatures above 900 ° C.