What is a mineral occuring in thin-bladed crystals and crystalline aggregates, of a sky-blue color. It is a silicate of aluminium. [Written also kyanite.] called?

cyanite — A mineral occuring in thin-bladed crystals and crystalline aggregates, of a sky-blue color. It is a silicate of aluminium. [Written also kyanite.]. (Webster's 1913.)

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