Monzodiorite and monzogabbro are intermediate plutonic igneous rocks containing plagioclase, alkali feldspar, biotite, hornblende and/or pyroxene. These rocks, together with monzonite, used to be called respectively syenodiorite e syenogabbro, due to their composition, lying halfway between syenites e diorite/gabbro in the QAPF diagram. However, the IUGS commission discourages the use of these terms. Modally, monzodiorite and monzogabbro contain more alkali feldspar (between 35 and 10% of all feldspars) with respect to their gabbroic counterparts. The difference between monzodiorite and monzogabbro is the composition of plagioclasio: more sodic in monzodiorite (< An₅₀) and calcic in monzogabbro (> An₅₀). Both may contain up to 20% quarzo or up to 10% feldspathoids over the felsic minerals. If quartz is more than 5% (but less than 20%) of the felsic minerals, these rocks can be classified as quartz monzodiorite/quartz monzogabbro. Alternatively, if foids up to 10% are present, they are foid-bearing monzodiorite (or monzogabbro). In the latter case, the term ‘foid’ in the name must be substituted with the most abundant foid present (e.g. nepheline-bearing monzogabbro). The content of mafic minerals (color index) of monzodiorites is typically between 15 and 50% and up to 25 – 60% in monzogabbros.