Differentiate between felsic and mafic rock-forming minerals?

Mafic is used for silicate minerals, magmas, and rocks which are relatively high in the heavier elements. 

Felsic, is used for silicate minerals, magmas, and rocks which have a lower percentage of the heavier elements, and are correspondingly enriched in the lighter elements.

Crystalline form Almkhaddh chemical composition of the metal minerals Nvsi