CRMhs is a formal extension of CIDOC CRM, building on CRMsci, developed to model scientific investigations in heritage science. It introduces dedicated classes and properties allowing heritage objects to be treated as epistemic entities within scientific workflows, capturing sampling, instrumentation, analysis, settings and resulting datasets as a traceable chain of evidence. This level of granularity supports the specific documentation needs of laboratories and institutions working with heritage materials, ensuring reproducibility and interoperability across disciplines. CRMhs has been developed and applied within major European research infrastructures, including ARIADNE and ARTEMIS, where it serves as the reference ontology for integrating scientific analytical data into Heritage Digital Twin frameworks.