You won’t find this at Crate & Barrel.Photo: Melissa HomFor your next birthday party, why not dine at a table that’s 300 to 500 years old? You can find just that at Irving Mill, thanks to the determination of owner-designer Sergio Riva. At a trade show he met the owner of Blue Ocean Traders and — sight unseen — purchased one of the 3,000-pound, six-feet-in-diameter millstones (used to grind flour, wheat, and the like) that the company sometimes receives from Egypt. How much does such a behemoth cost? Just $700 plus $2,000 for shipping, it turns out. “They must be giving these things away in Egypt,” Riva laughs. Actually, Riva’s particular stone came from western China. When he got it after weeks of nagging his supplier, he asked a friend to build (for $2,000) a 42-inch-high base made from steel plates so that patrons can use the artifact as a bar table. And boy if that doesn’t make us appreciate the wheat in our Spaten much more.