Magma /ˈmæɡmə/ (from Greek magma – thick ointment * a. magma; n. Magma; f. magma; i. magma) – molten fiery liquid mass predominantly. silicate composition, which occurs in the earth’s crust or upper mantle and forms tic rocks when solidified. In rare cases, magmatic melts Ex. Thanks to magma and its physical and chemical properties, deposits of metal ores are formed, which are the basis of the mining industry.