Introduction: Si and Mg isotopic compositions are indicators of evaporation processes experienced by CAIs [1]. Bulk Si and Mg isotopic compositions (up to ~5 permil/amu for Si and ~11 permil/amu for Mg) have been reported by [2]. Isotopic heterogeneity within CAIs is of interest because it may reveal how evaporation processes occurred. It may also reveal if secondary processes such as recondens...