As you know if you read our front page, my very first piece of "old" Fiesta was about a year old. Nobody was trying to fool me. The old line stopped in 1973 and the new line started in 1986, using a lot of the same shapes, and a lot of people honestly can't tell them apart. It isn't a question of which one is better. We collect both and we love both. It's only a question of knowing what you're buying, and what it's worth, and whether it's red enough to keep off the dinner table.

Here's what we do, in the order we do it. These are general rules from a couple of collectors, not an appraiser, and there are exceptions to every one. Use them together, never one alone.

Color is the first and best clue, because the two lines mostly used different colors.

That last row is where people get caught. An old turquoise and a new turquoise are both "turquoise," but set them side by side and they're plainly two different colors. The same goes for the two cobalts, the two roses and so on. Once you've seen a pair together you won't mix them up again, but on a blanket at a swap meet, all by itself, a piece can fool you.

Stephen's trick: we keep one old saucer in each of the shared colors, wrapped in a dish towel, in a shoebox in the trunk of the car. When we find a piece we're not sure about, out comes the saucer. People at swap meets think we're crazy. We are, but we're right.

Most old pieces are marked on the bottom with the word fiesta in lowercase letters, either pressed right into the clay or stamped on in ink, sometimes with the factory's initials and "USA."

But plenty of old pieces aren't marked at all, especially small things like cups, shakers and some of the bowls. And the new line is marked too. Its mark is different, but it's close enough to fool you if you've never compared them.

The best way to learn the new mark: go to any store that sells the new line and turn over a plate. Then look at the bottom of an old piece at an antique mall. Five minutes and you'll have them both in your head. And please, don't buy anything on the strength of the mark alone.

The new line is made of a harder, denser kind of china, more like what restaurants use. In our hands, most new pieces feel heavier than an old piece of the same size and shape. It isn't a sure thing, and you can't weigh pieces at a swap meet, but after a few years your hands just know.

Look at the wear, too. An old piece has usually been used for decades, and it shows: fine gray scratches from knives and forks across the middle of a plate, a little wear on the foot ring. A new piece that's been used for a few years can show some of that, but it's rarely as much. And look out for crazing, a fine web of cracks in the glaze. Old pieces can have it. We pass on anything crazed or cracked, no matter how pretty.

A lot of the old shapes were brought back in 1986 and after, but not all of them, and the new line has added plenty of shapes the old line never had. So if somebody is selling you an "old" piece in a shape you can't find in any book about the old line, be careful. Get a good collector's guide with pictures of every old shape and read it in bed until your partner complains. (Ask me how I know. — S.)

The old red is the famous one, and the one with the uranium in the glaze. It was made from 1936 until the war, and again from 1959 until the old line ended. The new line doesn't use that glaze, and none of the new colors is the same as the old red. If you've got the real orange-red, you've got an old piece, and that's the one we'd keep on a shelf and not eat off. If you're not sure, ask somebody with a Geiger counter. You'd be surprised how many collectors know somebody.

1. Color first. Only-old colors, only-new colors, and shared names in different shades.
2. Check the mark, but never trust it alone.
3. Feel the weight and look for honest wear.
4. Know which shapes exist in which line.
5. Old red is old. Admire it. Don't eat off it.

And the most important rule: if the price is too good to be true, it's probably new, and if it's high, ask questions. Most sellers aren't trying to cheat anybody. They just don't know. Be nice. Then go get your saucer out of the trunk.

— Alan, with interruptions from Stephen