Score plotofPC1andPC2.Variables:40 fitting parametersoftheRamanCH
bands, items:37referencesamples+20 archeologicalcopals(10internaland10
surface sampling).ThearcheologicalcopalsaregroupedwiththeAfricancopals.
Moreover,theinternal(IS)andexternalsamplings(SS)areinasamegroup
demonstrating thatageingisnot,toacertainextent,anobstacletothematerial
recognition.