IN ANTIQUES, there are experts on Chippendale, experts on Chinese armorial porcelain, experts on doll-house chairs and so on down to the experts on 18th-century brass key holes. But Gray Boone -- a short-haired Southerner with the biggest antique diamond ring you ever saw supported on one finger -- is the expert on the whole $4-billion (her figure) antique business itself.

She is editor and publisher of Antique Monthly, a 72-page newspaper with a paid ($11 a year) circulation of 100,000, probably the largest in the field. The newspaper covers the art, artifacts and antiques of the 19th century and earlier --as though the world ended in 1900. Even Victorian objects are treated as not quite up to snuff.

The tabloid is noted for its excellent color photographs and its wide coverage of the antiques and art events in London, New York, Washington and the West Coast that have an effect on antique collecting. The newspaper is read as much for its advertising (frequently in color) as its editorial content.

Boone also puts out the weekly, chatty, insider's "Gray Letter," a newsletter circulating (for $55 a year) to those who can't wait to read it in the paper. A recent letter, for instance, told about the sale at Phillips auction house in New York where Charles Dorman, curator at Philadelphia Independence Historical Park, found a rare desk. The desk, Dorman believes, is the only one of 30 made in 1790 for Congress Hall (in Independence Hall) to come on the market. Boone's newsletter quotes him as saying: "I will publicly jump off the tower of Independence Hall if I'm wrong about this desk."

Boone, 39, is a prime example of the Scarlett O'Hara tradition in Southern women -- hard-working, good-looking, fast-thinking, slow-talking and, above all, quick-calculating. She knows everybody who is or isn't anybody in the antique business, but she likes well-known names, old and new, and is good at dropping them (and picking them up). She's also a warm, charming woman who answers hard questions in an honest, straightforward manner. And she's young, trim and brave enough to wear harem pantaloons to the State Department's buffet for donors to the Diplomatic Reception Rooms (to the expressed pleasure of Clement Conger, chairman of State's antique collection).

In 11 years, starting out as a housewife with three children and a bad antiques habit, she has put together a remarkable number of enterprises, both nonprofit and thank-you-very-profitable-indeed, based on antiques.

Currently she is in Great Britain as troop leader to 85 antique dealers who have gone to learn not only why British prices for antiques are so high but also where to research the pieces they already have paid for. The trip is not the most profitable of the Boone enterprises. "We had hoped for 100, but prices are so high in England now, and currency fluctuates so much, that the trip wasn't as popular as we'd hoped. Starting now, I wouldn't try to organize it again," she said.

Once a year, Boone assembles a seminar at New York's posh Pierre Hotel with a group of experts who know as much about the business of antiques as anybody ($225 tuition for the two-day program). There were 225 people registered for this year's seminar, but the whole Chicago contingent was snowed in at the airport and never made it. The event honored Henry Kissinger as the person who did the most in 1977 to promote antiques, on the somewhat dubious grounds that he arranged for King Tut's tour of the United States. "I think King Tut has done a lot to make people think about their roots," Boone said the other day.

Conger, who is also White House curator, was her first antiques man of the year, in 1976. He says of Boone, "She's a smart girl, and unique in her field. Of course Antiques magazine is the standard, much more authorative, but it is timeless. But Antiques Monthly is newsy, we clip articles from it for our files. I think its color printing is outstanding. And they have so much of it."

Orva Heissenbuttel, a Washington area antiques writer and collector who once worked for Boone, said, "Her newspaper has lots of color and extensive coverage. It really covers antique news in depth, rather than the shallow approach of some of the other antiques tabloids. The other well-known ones in the field are Antiques Trader, a weekly with a high circulation and a great number of classified ads; Collector's News, American Collector and Spinning Wheel."

Boone does very little actual writing for either the "Gray Letter" or Antique Monthly. Executive Editor is Kellee Reinhart, a bright, hard-working 26-year-old journalist. She and Anita Mason do most of the research, editing and writing for both. "But Gray reads every page of the newspaper and every word of the 'Gray Letter' before either goes out. Though she's our corporate symbol, so to speak, she does contribute a great deal. Of course, she's in London, New York and all over so much, she really knows what's going on," says Reinhart.

Like most journalists whose expertise comes from on-the-job-training, neither Boone nor Reinhart claims expert knowledge of antiques. Reinhart says "We're not antique experts, we're generalists. Though I'm always surprised, walking through shows, at how much specific knowledge she has."

Recently, Boone organized the Decorative Arts Trust, with the help of Dewey Lee Curtis, curator of Pennsbury Manor, Morrisville, Pa.; Richard Howland of the Smithsonian and Charles Wall, recently retired as director of Mount Vernon. The trust is set up to provide a national speakers' bureau, regional forums, lecture series and, eventually, to provide a computerized registry for decorative arts objects.

"Collections could be logged with us. Someone in a historic house in Texas with a Maine tilt-top table could find someone in Maine who was looking for such a table. It would also be a grand way to hunt down stolen items," Boone said at lunch during one of her brief visits to Washington.

On the side, Boone is also a director of the South Central Bell Telephone Co.

In the thick of the business, Boone denies any intention of building her own great collection of 18th-century salt spoons, or any other such fancy, though she has told people that she originally started Antique Monthly so she would have a way of paying for her forays into antique shows and shops.

"I did have a collection, a small one, of antique jewelry, which I love," she said. "But in New York not so long ago, on my way back from London, someone cut my pocketbook handle, and stole it -- along with, of course, the best pieces of jewelry I owned.Since then, I've decided to give away my small collection of Alabama silver tableware or sell it. I really don't want anything that's easily stealable and transportable."

Boone's husband, James, on the other hand, collects newspapers -- 23 in 10 years at last count, including the Tuscaloosa (Ala.) News, their home paper. His father, Buford Boone, won a Pulitzer Prize in 1956 for his editorial criticizing Gov. George Wallace for trying to keep a black student from enrolling in the university of Alabama. The elder Boone, a native of Macon, Ga., had quite a time with the ensuing strikes, boycotts and other expressions of displeasure with his stand.In 1968, he sold the Tuscaloosa paper to his son, who had been publisher of a newspaper in Suffolk, Va. Gray and James Boone met and married in Baytown, Tex., her hometown, when he was working on a newspaper there.

Gray Boone says today she is on her own but admits that early on her husband gave her a great deal of advice, sitting at the kitchen table, on how to run a newspaper; her previous work experience was as a legal secretary.

For the anniversary issue of Antique Monthly, she explained how she learned. The babysitter would come after dinner, and she and her husband would go to his newspaper's composing shop, set type and headlines, paste up the pages and proof them. "Jim would lay out the pages first then tell me how many typed pages to write my stories and what kind of pictures to take. If he planned a horizontal picture, I was supposed to hold the camera sideways and if it was a vertical, I just held it straight up and shot away." Boone's birthday present in 1968 from her father-in-law -- she calls him Grandpa Boone -- was an ad for her newspaper in Southern Living magazine.

The Boones obviously travel much of the time, with the help of two airplanes they own. "Lots of times he has breakfast with us, flies off to see how one of his papers is doing elsewhere in Alabama, North Carolina, Mississippi or Iowa, and then back again in time for supper. When I'm away from home it is more like two weeks or so a time."

The Boone children, Kenneth, 17, Buford, 16, and Martha, 15, go to Tuscaloosa public schools, but travel to England when they can with their mother. Once they all stayed on a big estate where a Rolling Stone concert was held, and that made up for a lot of mother's travels.

Meanwhile, back in their antebellum (that's the proper Southern term) mansion in downtown Tuscaloosa, peace is kept by a live-in governess, described by Boone as "a grandmother substitute" who plans the meals and drives the children where necessary. A full-time maid and a parttime handyman complete the household staff.

At Antique Monthly, a shoestring staff of 13 works in a pleasant 1905 cottage Boone recently bought ($65,000) for its offices. The cottage is three blocks from the Boone house. The four salesmen, according to Boone, are bringing in advertising sales that have gone up an average of 20 percent each month for the last 10. There are two correspondents in London, two in New York, one each in California, Australia and Washington (Hope Ridings Miller), and stringers elsewhere.

"We hope to print an edition in Australia soon. There's nothing else like us there. We do have subscribers from all the English-speaking countries," Boone said.

Boone and the Jimmy Carters have something in common beside the large white pillars on their front porch: E:ward Vason Jones, the Albany (Ga.) architect who has served as White House curator Conger's consultant on the White House redecoration.

Jones, who also has been a consultant for the Metropolitan Museum of Art's American wing, planned the restoration of the Boones' 1835 house. The house, right in midtown Tuscaloosa, had stood empty for 12 years. It took more money and time than they care to count to restore the house. But today they think it's worth it -- if only to serve as the proper setting for the editor/publisher of Antique Monthly. The house has about six rooms on the first floor, four on the second and three in the basement.

"We have a few good antiques --mostly Duncan Phyfe -- and, I'm ashamed to admit, two beds, 1876 centennial reproductions of earlier designs, that I bought before I knew better."

They have a log cabin on a nearby lake, furnished by Boone with Southern primitive art. It is mostly used for business conferences, Boone said. Her husband invites business acquaintances for lunch there, away from the telephones, and cooks steaks for them. Gray Boone admits James Boone is the family cook, though the boys help.

Boone believes the antique business is swinging ever higher: "I think the volume in the United States perhaps increased by a billion last year -- that's a guess based on the sales of Sotheby Parke Bernet, Phillips and Christie in New York and the antique shops across the country. I think our business about equals that of Great Britain and the continent."

Even though Boone is showing the American dealers around Britain this week, she says she believes the United States is a better place to buy antiques. "Antique dealers are coming to the United States, buying English goods and shipping them back. Only American silver is cheaper in England than America."

Boone sees American antiques as the biggest-selling style, with Oriental close behind, followed by English with French antiques at the bottom.

Whatever's up, whatever's down, you can bet Boone's out there pacing it.