[ Well, why would Hermione know when jeans were first invented? Fashion is definitely not her hyperfixation, illustrated here by the fact that she accepted whatever change of clothes the Rift gave her on orientation and is still wearing them. Robes, too. ]
Ah - they're denim trousers. Rougher, but more durable. Usually blue.
this might be my favourite tag
Ah - they're denim trousers. Rougher, but more durable. Usually blue.