The precursor material of Portland cement (PC) colloquially referred to as clinker is produced primarily via calcination of limestone (CaCO₃). Magnesia-based cements can similarly be formed via calcination of magnesite (MgCO₃) among other routes. Dolomitic minerals typically contain a mixture of these carbonate mineral phases. The current study monitors and explores the electrochemical transformation of CaCO₃ and MgCO₃ synthetic mixtures approximating dolomite and investigates their applicability in forming cementitious phases. The transformation of such mixtures indicates that Mg- and Ca-based electrolysis products, namely Ca(OH)₂ and Mg(OH)₂, respectively, display different precipitation parameters. Mg(OH)₂ precipitates more rapidly in the form of flower-shaped micro-aggregates, while Ca(OH)₂ forms slower in comparison, precipitating in larger hexagonal prismatic structures. These findings point toward possible mixture separation techniques for PC and magnesia-based cements.