"My grandmother only wears gold jewelry."
Translation:Ma grand-mère porte seulement des bijoux dorés.
But "en or" should be accepted here, as the sentence could mean that my grandmother refuses to wear gold-plated or gold-coloured jewelry and only wants the real thing. This problem is everywhere in this new lesson. They have introduced the new words "doré" et "argenté" which refer to the colour rather than the material, and they are insisting we only use them, even in cases where "en or" or "en argent" would work equally well.