The Nevado del Ruiz Volcano (northern Andes, Colombia) displays calc-alkaline affinity from medium to high potassium content. NRV porphyritic dacitic-andesitic lavas have diverse plagioclase populations, amphibole breakdown rims, pyroxene corroded cores, and magmatic enclaves reflecting magma chamber instability due to melt composition abrupt changes during crystallization related to fractionation and magma mixing. Analysis of lava flows samples of the NRV eruptive periods shows that crystallization of pyroxene occurs at 1022°C for Pre-Ruiz (1,8 to ca 0,97 Ma), 955°C for Second eruptive period (66 ka - recent), and 930°C for Cisne Volcano Lavas. Newly reported 40 Ar/ 39 Ar ages together with published data shows a moderately good correlation with interpreted NRV evolution stages and indicate a quiescence in magmatic activity from ca. 550 ka to 680 ka. NRV geochemical, petrographic, and isotopic data indicates that magmatic petrogenesis was controlled by partial melting of a metasomatized mantle wedge with hydrous fluids from the subducted slab. Magmatic evolution was controlled by fractional crystallization and local crustal contamination. The evolution of the recent lava flows was controlled by periodic replenishing of magma producing geochemical variation at cm scale.