From http://schema.org/docs/datamodel.html:
The canonical machine representation of schema.org is in RDFa:
schema_org_rdfa.html
(See my answer on Webmasters SE for other representation.)
This HTML+RDFa version uses the RDFS vocabulary. It’s as good as any other RDF serialization. If you don’t like RDFa, you could of course use your favorite converter to get Turtle, RDF/XML, or whatever you prefer.