A dichroic violet-blue to gray mineral silicate of magnesium, aluminum, and sometimes iron.
A bluish, very hard, pleochroic, crystalline mineral, magnesium aluminum silicate, (Mg,Fe)2Al4Si5O18, used sometimes as a gem.
A light-blue to dark-blue or gray orthorhombic mineral. Cordierite is a silicate of magnesium, aluminum, and sometimes iron, and is found in granites and in metamorphic rocks that form under relatively low-pressure conditions. Chemical formula: (Mg,Fe)2Al4Si5O18.
Origin of cordierite
- French after Pierre L. Cordier (1777–1861), French geologist
From American Heritage Dictionary of the English Language, 5th Edition