Stishovite is a form of silicon dioxide that is formed at very high pressure (~ 100 kbar) and temperature (> 1200 ° C), so far as is known only in meteorite impact craters and their ejecta. For properties see [1] and [2] The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ... In volcanology, ejecta consists of particles that came out of a volcanic vent, traveled though the air or under water, and fell back on the ground surface or on the ocean floor. ...
and for its relationship to impacts see [3]
Related mineral: see Coesite Coesite is a form of silicon dioxide that is formed when very high pressure (2–3 gigapascals) and moderately high temperature (700 °C) are applied to quartz. ...
Stishovite is a polymorph of quartz and the other members of the quartz group, meaning that it is composed of the same chemistry but has a different structure.
Comparing stishovite's density and index of refraction to that of quartz's, 4.28 to 2.65 and 1.81 to 1.55 respectively, it is hard to believe that they are both composed of the same elements and in the same proportions.
Stishovite's structure is made of parallel chains of single octahedrons composed of a silicon ion surrounded by six oxygens.
Stishovite is also among the strongest known oxides, and understanding its elastic and rheological properties is fundamental to the search for new superhard materials.
Stishovite was loaded into a diamond anvil cell and compressed non-hydrostatically.
This study of stishovite provides an example of how recent developments in diamond anvil cell technology together with synchrotron x-ray diffraction techniques are yielding new advances in our understanding of fundamental quantities, such as elasticity and yield strength, of strong materials under extreme pressure conditions.
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