What is a mineral consisting principally of silicate of iron, and crystallizing in hexagonal prisms with perfect basal cleavage; -- so named from the Swedish mineralogist Cronstedt called?

cronstedtite — A mineral consisting principally of silicate of iron, and crystallizing in hexagonal prisms with perfect basal cleavage; -- so named from the Swedish mineralogist Cronstedt. (Webster's 1913.)

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