Editorial for the Special Issue "Minerals of Alkaline Igneous Rocks: Chemical and Isotopic Features as Tracers of Magmatic Processes".

Sun et al. [[44]] performed a highly accurate mineral chemistry investigation and found an unusual mechanism of substitution in these pyrochlore supergroup minerals involving Nb and REE. This Special Issue aims to highlight the pivotal role of the minerals found in alkaline igneous rocks in tracing magmatic processes. The detailed mineral chemistry characterization carried out by D'Antonio et al. [[33]] instead highlighted that the clinopyroxene present in the MEGT products collected near the vent area on Ischia, which is still variable, never reached the aegirine composition. Hence, the chemical composition of minerals coexisting in an igneous rock can yield estimates of the pressure-temperature-oxygen fugacity (P-T-fO SB 2 sb ) conditions established during specific stages of magma crystallization (e.g., [[1]]). [Extracted from the article]