柯林斯詞典orthoclase /???θ???kle?s, -?kle?z/ 1. N a white to pale yellow, red, or green mineral of the feldspar group, found in igneous, sedimentary, and metamorphic rocks. It is used in the manufacture of glass and ceramics. Composition: potassium aluminium silicate. Formula: KAlSi3O8. Crystal structure: monoclinic 正長石 返回 orthoclase