diff --git a/lib/pyld/jsonld.py b/lib/pyld/jsonld.py
index 49d6212..54fe4b4 100644
--- a/lib/pyld/jsonld.py
+++ b/lib/pyld/jsonld.py
@@ -3545,10 +3545,16 @@ def _graph_to_rdf(self, graph, issuer, options):
                     continue
 
                 for item in items:
-                    # skip relative IRI subjects and predicates
+                    # All IDs should be absolute at this point in time
                     if not (_is_absolute_iri(id_) and
                             _is_absolute_iri(property)):
-                        continue
+                        raise JsonLdError(
+                            'JSON-LD graph conversion error; '
+                            'invalid IRI for property or ID, '
+                            'IRIs must be absolute',
+                            'jsonld.RdfError',
+                            {'@id': id_, 'property': property},
+                            code='invalid IRI')
 
                     # RDF subject
                     subject = {}