Typomorphic features of tourmalines of the Malkhan pegmatite field from the Irkutyanka vein

Jade or "Fei Cui" are trade names for a stone that typi- cally contains only one or more main minera

Noble gases —elements of the last column of the periodic table—are chemically defined by their f

Malacacheta, located in Minas Gerais, Brazil, is renowned for its alexandrite deposits and com-plex