You're making mixed medium jewellery :-)
Jewellery is the art form. The medium is the materials from which is is made. Mixed medium usually refers to using different types of materials within a piece. Usually (in jewellery) it's used with reference to using a mix of say traditional beads and wood, paper or fabric (or concrete or plastic... you get the idea!) . But if you're talking about a collection of different jewellery items, some made with porcelain, others made with glass or crystal or chain maille then as a collective, your jewellery would be mixed medium...
In the context of an ART show I'd say the answer is jewellery, mixed mediums. In the context of a JEWELLERY show I'd say mixed medium.
That's my understanding anyway (says she who only ever makes jewellery with erm... crystal...)