Well, coral seemed extremely common in the paperweights that I looked at, many of them glass. Coral, in fact, is farmed pretty much all over the world for use in saltwater tanks and, I imagine, other kinds of decor (and more recently to replenish dwindling reefs). I don't doubt your expertise here, and perhaps you're using an industry definition, but my dictionary doesn't define antique as something in excess of hundred years of age, but merely something that is leant particular value because of its considerable age.
The item I'm describing was narratively significant in the book Nineteen Eighty-Four, which as you may know, was published in 1949. I always got the impression from the author's description that it was the kind of thing one saw fairly often in curio shops when he wrote the book. If you're telling me that this item was entirely a figment of George Orwell's imagination, that's exceedingly disappointing. The book is my boyfriend's favourite and he's agreed in the past that the paperweight the protagonist invests with such sentimental value would be the "perfect gift." It would mean a lot to me to find something that approximates my description. I'm sorry that you're so certain I won't. That's a really big blow to me.