"Your new silver shoes are great."

Translation: Tes nouvelles chaussures argentées sont géniales.

[DaveyElder]

Can't use "magnifiques"?

[DaveyElder]

Or "grandes"...

I know this might imply great in size but so could the English sentence.

[TimmyKilminster]

No, you'd never hear a native speaker use "great" for "large" in such a context.