To be clear, you are looking at the photographs in the linked article, and asserting that you think it's not a fossil?

It's visibly very clearly a fossilized sea shell. You are being a useless pedant about the author's choice of verbiage.

Well, it's your words against his. You're not much of an expert by your own account in other comments. It's irrelevant if it's from a correct geological period, it's a rock hard seashell. Go and read up the definition of "fossil".