( n. )
A mineral of a transparent vitreous brown color, found in the ejected masses of Vesuvius. It is a silicate of iron and magnesia, containing fluorine.
( n. )
A mineral of a transparent vitreous brown color, found in the ejected masses of Vesuvius. It is a silicate of iron and magnesia, containing fluorine.
Webster's Revised Unabridged English Dictionary. Пересмотренный полный словарь английского языка Webster. 2012