2005/09/14 | 堇青石[Cordierite]
类别(℃〖化学〗) | 评论(0) | 阅读(28) | 发表于 23:06
A cyclosilicate mineral sometimes used as a gemstone. It has the composition (Mg,Fe)2Al4Si5OH2O. It has an extremely low coefficient of thermal expansion and is therefore made synthetically by baking clays in a furnace for use in catalytic converters (where the cycle of hot and cold do not cause it to fracture).
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