01 n. A mineral of a black color, submetallic luster, and high specific specific gravity. It is a niobate (or columbate) of iron and manganese, c…
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A mineral of a black color, submetallic luster, and high specific specific gravity. It is a niobate (or columbate) of iron and manganese, containing tantalate of iron; -- first found in New England.(Min.)