A friend of mine collects these - I wouldn't mind one myself as a decanter, but they fetch around £300 each when intact, so I have not bothered to buy one.
I was watching a mechanical digger cut a service trench on the site of my old workshop in town some years ago, and as it dropped a bucket of hard earth onto the ground beside it, I saw a perfectly intact, Roman glass bottle roll out and come to rest on the bank. As I reached down to pick it up, a great clod of earth landed on it, smashing it to pieces. The thing had sat there for about 1800 years, then broke just as it was about to be saved.
The Eastern approaches to Bath are absolutely saturated with Roman and later remains - I saw the bones of a Middle-Eastern trader discovered in Walcot street, stuffed into a box in the cellars of the Roman Baths recently. Right next to the little cardboard box which was his last resting place, an archaeological pathologist had reconstructed his face using the skull as a base, and he stared at me across the years, down in the dark passages of the Baths. Those reconstructions are extremely accurate, as shown by modern murder cases which have been solved using the same technique.
It is crazy, but you can buy Roman glassware for a fraction of the price that the 18th century equivalent costs - cheaper than the Romans bought it for 2000 years ago. A roman drinking glass cost the equivalent of about £3000 in it's day. It would now cost you about £200.