I would say if you really like that piece of jewelry, there's no reason not to wear it. As long as it doesn't have any logos or anything like that.
But, jewelry is rather small and not that many people know what a classic Cartier bracelet looks like, for example. With bags, they're more of a focal point of an outfit than a ring or a necklace. Personally, I wouldn't wear something that was an exact copy or a famous design, even if it didn't have any logos and therefore wasn't, strictly speaking, a fake.
But if it's inspired - that's a totally different thing, in my opinion. Lots of brands copy each other. Saint Laurent Manhattan looks somewhat like a Kelly. Lots of Saint Laurent, Gucci and Prada quilted bags have been inspired by Chanel and their Classic flap.
There's also the Box bag - Hermes Constance, Celine Box, Prada Don't remember what it's called, and many others.
And don't forget high street and contemporary brands getting inspired by designer bags, sometimes almost too close. Case in point: Prada Galleria and Tory Burch Robinson.