Petrology of the hypabyssal kimberlite of the Kroonstad group II kimberlite (orangeite) cluster, South Africa: Evolution of the magma within the cluster

► Kimberlite magma evolution within a single cluster. ► Evolution linked to olivine macrocryst/phenocryst abundance a ratio. ► Evolution linked to possible early contamination by crustal material. ► Identification of pseudomorphed monticellite and melilite in a Group II kimberlite.