The Washington Antiques Show opened its five-day run yesterday at the Shoreham Hotel and by noon, the hour it opened, a little line had formed of early birds keen to see the newest things in yesterday's bric-a-brac.

Ares, who you may have thought was the god of war, turns out to be a pleasant woman from New York who sells antique jewelry.

"Now that is a perfectly delightful little Victorian necklace," said a fellow who rarely buys necklaces and suspected this one was a trifle more than a copper bracelet. "TLook at allthose colors. What's the green?"

"emeralds," said Ares. "All from different mines.

"They are about as flawless as emeralds get," she went on affably, "and as you say they look better than the sapphires. The necklace was made in 1840 for Lucy Duff Cooper's marriage. It's $75,000."

The stones were green, blue, yellow, mauve, with lots of pearls and whole thing would look nice on the neck of an 18-year-old girl. Innocent and artless.

If I were a vandal," said Ares, "I'd break it up and make four rings of the four emeralds. You don't often see them that quality. Say $10,000 a carat." "Maybe you should be a vandal," said the fellow who concluded the necklace was too much for a kid's birthday.

"Never," said Ares. "might charge more for the necklace, but I'd never break it up. Even though it would bring more money that way. I am first of all an antiques dealer - in antique jewelry. I don't have pretty high standards and I don't compromise. It has to be both old and beautiful.

"Look at this ring of sapphires set with diamonds. Five thousand, I believe. Where are you going to get matched stones like that at that price at Tiffany's or Cartier's or Van cleef?

"All a fellow is gong to get at Tiffany's, if he's looking for an engagement ring, for $1,500 is a diamond with four prongs to holding it."

Ares demonstrated that a whale of a lot more than four prongs was going on in her antique rings, and said thank God so many young people were discovering they could get more for their money in antique jewelry than in modern shops. And you needn't expect the big jewelers to come up with any very inspired designs, either - not like this pin with the canary diamond and the detachable diamond flowers and look here how this unscrews and you could use it in the hair, of course, as well as . . .

Leaving Ares before spending his last $75,000 ("and whoever buys it will be getting a very fine value, at that," Ares said) the visitor could make his way among the 44 booths, each operated by a different antiques company. Some had come from Maine, others from Long Island, Pennsylvania, Mississippi, Florida and romantic Alexandria.

If anyone felt faint, either with desire or from shock, he could revive himself with a $2.50 lunch being served from a buffet right there in the show, with chairs and tables.

The early crowd seemed middle class - that is, neither tiaras nor bare feet were asking prices (many of the objects have the price marked, but people still liked to ask).

Yonder was an 1890 weathervane for $1,500 that compared favorably with the copper eagles at a Wisconsin Avenue hardware store for about a tenth the price. And over there were some blue and white Chinese plates, somewhat exalted over the days when you could pick one up for a buck.

"The ducks?" repeated a print dealer when someone asked how much the big Havell aquatint of a couple of ducks was. "Three thousand dollars."

Or therabouts - the inquirer knew he did not want that particular print.

"Is that pretty much the going price or is there something remarkable about that particular one?" asked the fellow.

"Oh, you can pick up one for $650 if you'll settle for a couple of sparrows or something like that that nobody wants. But if you want ducks, this is the best we've got."

Mrs. Elisha Hanson said Lord, nobody could afford antiques any more, but she had come to look, anyway.

"Well, at least you can see how much all your old furniture and things are worth now," someone said.

"Much good that does," she said, casting an eye over some export porcelain. "I could never sell any of my things, and it just means you have to pay more for insurance.

"It used to be, you know, that thieves never stole antiques. Even in silver, they always stole the new silver stamped STERLING. I guess they couldn't read the old hallmarks and figured the 18th-century silver was plated.

"But now they have gotten pretty knowledgeable, I understand," she said.

In one booth there were beautiful painted silk screens, in another there was a good-looking silver bowl made in the Orient to please (its makers hoped) Western taste. Here an old brass sundial, there an old leather water bucket. A fine 18th-century chest from Philadelphia in one booth and quite practical little bachelor's chest in another.

John Fifield, who put together the show, said he has a neat waiting list of firms that would like to show. A booth may cost $600 for the five days, and various dealers said they found the show quite worthwhile judging only by sales at the show, to say nothing of the advertising value:

"The week after the show will be a madhouse at our shop," said John Blair of John Blair, Ltd. at Bethesda. "Always is."

Blair said the price of antiques has risen pretty much in tandem with the dollar's inflation:

If beef sells for a quarter a pound, prices will fall. It goes to two dollars a pound, prices rise," he said.

He used to breed Dobemans and notes a similarity between the dog market and the antiques market:

"You can always sell the champion," he said. "Especially since antiques have become so popular with investors, you can sell your very best - and therefore most expensive - things. You may have trouble with good run-of-the-mill things. Like the dogs, the top champions will sell.

"This morning I sold the most expensive piece of furniture I have here at the show that little bachelor's chest for $11,000."

And unlike stocks and bonds, of course, you can storesocks and shorts in it. CAPTION: Picture 1, Walnut veneered lady's desk from John Blair, Ltd. of Bethesda. By Harry Naltchayan - The Washington Post; Picture 2, Antique dealer Ares wearing a $15,000 enamel and gemset Swiss necklace with earrings and pendant. By Harry Naltchayan - The Washington Post