TODAY SILVER prices stand at $7.50 an ounce, and rising.Hardly anyone now can display the amount of silver tableware once owned by the John W. Mackay family, whose fortune came from the Comstock Lode mines of Virginia City, Nev.

In the late 1800s, Silver King Mackay sent Tiffany & Co. a half ton of silver from his mine to have made into a 1,250-piece service for 24. It took 200 men one year (1878) to make the tableware and nine chests to hold it.

Still, even with its high price today, silver arouses a great deal of interests, not to say madness. Some people are buying silverware on the theory that in a few months silver will be worth $10 an ounce-and in the meantime you can eat with it, which is more than you can say for stocks. Silverware stores have quit handing out advertising brochures because the prices of place settings change so rapidly.

A good way to learn before you buy is to take time to look at the exhibits of silver in the Washington area. The Woodrow Wilson house at 2340 S St. NW is exhibiting (until Sept. 4) "A Taste of the '20s"-tablesettings for breakfast, tea and dinner.

The Renwick Gallery offers "Olaf Skoogfors, 20th-Century Goldsmith" (until Aug. 19), showing tableware as well as jewelry, plus a sales show of silver, pottery and glassware in the shop.

The newly organized Washington Guild of Goldsmiths Spring Show (and sale) with flatware, holloware and jewelry continues through April at Glen Echo Gallery in Glen Echo Park.

The Garvan Collection of silver from Yale is currently touring the country. It won't make it to Washington but it will be at the Carnegie Institute art museum in Pittsburgh April 26-June 17 and at the Virginia Museum of Fine Arts in Richmond, Sept. 19-Oct. 19.

All year around, there are constant tabletop silver shows at the department and jewelry stores and specialty shops such as Martin's of Georgetown. Even more variety, though don't count on finding 12 forks to match, can be bought in the consignment shops such as the Bombe Chest on upper Connecticut Avenue NW and the Christ Child Opportunity Shop in Georgetown.

The Georgetown Silver Shoppe has stacks of old silver, mostly from 1870 to the 1930s. Probably the largest lode of old silver is in the many antique shops at Thieves Market on U.S. Route 1 south of Alexandria. Handsome pieces of silver turn up often in Washington in auctions at C.G. Sloan & Co. and Weschler. Weschler's next auction is May 18-20, Sloan's is April 19-22. Not long ago, a splendid antique show at the Armory had enough old silver on sale to rival the London Silver Vaults.

The more expensive and earlier English Georgian pieces, of course, you'll expect to find at the higher-priced antique shops. But the rage is beginning for the less-expensive though more ornate late Victorian and early 20th-century pieces. Gray Boone, publisher of the Gray Letter and Antiques Monthly, says that silver of this period is still one of the good bargains in antiques. The Mackay Service . . .

According to "Tiffany Silver," a fascinating book by Charles H. Carpenter Jr. with Mary Grace Carpenter (Dodd, Mead), the Mackay service included the things you'd expect such as gravy tureens and salad bowls. But there were also silver cups and saucers, scallop dishes, "segar" (as it was spelled) stands, crumb trays, salon lamps and two extinguishers, to name a few. All were heavily ornamented in the "East Indian" style with flourishes of flowers mostly in repousse (raised) work.

The centerpiece weighed 125 pounds and even back then cost $10,321.52. Carpenter thinks it has since been melted down. Major pieces bore the motto, appropriate to their weight, "Et Dieu Mon Appui" ("And God My Support").

In those days, washing the silver after a formal meal was a job indeed. Not to mention the problem of the dinner guests, who must certainly have had to keep their wits about them as they worked their way through the great number of pieces set at each place.

Tiffany & Co., in its 1880 catalogue, offered spoons for every food: berry, egg, grapefruit, ice, bonbon, ice cream and jelly-and a mustache spoon with its partial cover to strain out hirsute ornamentation. Other spoons included olive, orange, preserve, sherbet, toddy, mustard, pap medicine, salad, salt, sugar and vegetable.

Sometimes today, if you're fortunate, you can find a spoon or two of the more remarkable shapes in antique or not-new shops. The grapefruit spoon with a narrow end and the ice-cream shovel with a blunt end are especially useful.

The knives are not as practical. Most have the old nonstainless steel blades. Either you have them replaced or expect to see your guests secretly wipe them on the napkins. The only way to clean the blades is with a gritty cleanser or sand, and then they still look grimy, though they cut through the toughest steak.

In Vienna between the wars, a certain elegant lady consoled her two daughters at the poverty of the wedding gifts they received by explaining they would not be expected to entertain in the manner in which she herself was accustomed. She cut her banquet cloth, made for a table seating 24, in two, and gave each daughter silver place settings for 12. Muttering, of course, how hard times were.

Of course, her household was modest beside the society family in Prague who in the '30s lived in the mansion that is now the Chinese Embassy. Their silverware was kept in the silver vault, an armored room next to milady's chamber. This family had service for 48, but then they had a great many relatives.

Former President and Mrs. Woodrow Wilson lived far more quietly than that when they moved to their S Street residence after he retired from office. It is said that although poor health prohibited him from attending dinner parties, he urged his wife to keep her spirits up with small gatherings. Usually during the course of the evening, Mrs. Wilson would slip away for an hour or so to say goodnight to her husband and then rejoin her guests for brandy.

All the Wilson silver was, of course, distributed to relatives. But guest curator at the residence, Patricia de Lashmutt-Robbins, has borrowed silver to illustrate the major tastes of the '20s. She points out that the "blend of nostalgic, avant-garde and exotic decorative influences produced a comfortable milieu of past and future." All of this at the time when Elsie de Wolfe, the trendy decorator, was pushing neutral colors, bare floors and greenery-much as her successors are today. Wilson's Quiet Elegance

The Wilsons' charming breakfast room, a sunny south bower glimpsed through the hall's Palladian window, is such a room. Such a perfect place for breakfast. De Lashmutt-Robbins has set it with Coalport china and King Albert sterling, lent by Four Winds Antiques of Alexandria. The pattern, classical in shape, has floral detailing. It was made in 1919 by Whiting division of Gorham. Then as now no one minded using non-matching silver for service pieces. The butter knife and sugar. shell are Violet pattern, circa 1905, by William A. Rogers. The jam jar has a lotus design, reflecting the 1922 discovery of King Tut's bomb. Instead of a cloth, there are small round place mats.

The toast warmer, electroplated nickel silver (an alloy with no silver in it), has a holder for the bread and a burner underneath to keep it warm. The coffee pot, creamer and sugar are silver with spiral gadrooning, made by Tiffany and Co. and lent by Decatur House.

The effect is pleasant, but so carefully arranged that you surely would not come down in anything less than a boa-trimmed negligee and a silver clasp in your hair to match your husband's velvet jacket.

The tea setting is more advanced, featuring an elaborate linen cloth with zodiac motifs, a craze of the time. The china is a startling pseudo-peasant floral by R. & S. Mrazek Manufacturing Co. It would seem more appropriate for family breakfast than for the more formal company tea. But the flatware is the terribly elegant Georg Jensen Pyramid pattern, designed by Harold Nielsen of Art. The silver is a prime example of why art deco is sometimes called "Aztec Airways," with its plain handles ending in a pyramidal finial.

The porcelain flower vase here by Lenox, with a simple white body and a restrained gold base, shows why Mrs. Wilson thought Lenox was good enough to be the first American-made White House china service. The plates are glass with a neat art deco monogram.

The dinner table is not as interesting, though the Rosenthal, Bavarian porcelain with a deep ruby border, is handsome. Surely Mrs. Wilson would have insisted that the tablecloth, beautiful lace though it is, cover the ends of the table and come down a foot or two. The flatware is, as you'd expect, traditional sterling by Tiffany and Co. in the "English Kings" scroll pattern, lent by Decatur House.

The vase, however, is something more, favrile glass by Louis Comfort Tiffany. The candles, as befits the time, are set in sterling silver sticks with silver filigree shades, backed with red silk-fringed of course.

The dessert service is one of the most beautiful of all patterns, the Lap Over Edge service of about 1890. Each piece is different, hand-ornamented with raised three-dimensional bugs, beasts, flowers and fruit applied in copper, gold and silver. This pattern was made in limited quantity because it was so expensive. Occasionally, if you're lucky, you can find a piece for sale at quite a price. Wilson House borrowed its service from Lyndhurst, financier Jay Gould's former mansion in upstate New York. Tiffany, according to the Carpenters, has made only six especially commissioned silver services-one of those for J. Carter Brown, a predecessor of the current director of the National Gallery of Art. Skoogfors' Hallmark

Olaf Skoogfors' silver at the Renwick is far simpler-since it was made in the 1950s and '60s in Philadelphia-but nonetheless masterful. Skoogfors is considered by his colleagues all over the world to be one of the most important goldsmiths of the American craft revival. He worked only 23 years before his death in 1975.

The jewelry in the show is beautiful, strong and abstract. The pieces resemble cosmic elements-the ground with a crack like an earth-quake, a shape like a planet, surfaces crackled like moon scapes. All are set with single pearls or diamonds.

The holloware is strong. The sterling candelabra are illustrated in many standard works on silver. The series of six cups for candles encircles a seventh, all supported by sinuous curves. The Weeders Trophy, 1958, is in the English arts and crafts style. A silver skillet, pitcher and coffee pot all have practical wooden handles so the holder isn't burned.

This retrospective was organized by the Philadelphia College of Art with grants from the Pennsylvania Council of Art with grants from the Pennsylvania Council of the Arts and the National Endowment for the Arts. Washington's Goldsmiths

The Washington Guild of Goldsmiths show at Glen Echo is splendid work. (All workers in fine metals call themselves gold smiths.) Much of the show is jewelry. Not many today are willing to spend the money for the amount of silver holloware and tableware requires, not to mention the uncertainty of sales.

Fortunately, Susan Tamulevich and Komelia Okim are two of that rare company. Their work is imaginative in design and splendid in technique. Their work in hollow and flatware is more decorative than Skoogfors', reflecting the freedom craftworkers of the '70s feel.

Tamulevich's pieces are delicate. She makes a charming variety of spoons-and who could imagine so many handle shapes: leaves, a grill design, hooks, scallops, a sheaf. Bowls of the spoons are equally imaginative.One ladle has a heart-shaped bowl; another is squared. A baby spoon comes with a rattle at one end. The temptation is to stuff them in your pocket and run.

Okim's work is fanciful as well. A wine decanter is crowned with an uncut amethyst crystal. The teapot and creamer have curving handles fastened only at one end (which might be difficult to negotiate when full). The tops of the pot and sugar have spires, rather as though they originated on Krypton. Strangely, a bowl or bun warmer is fur-lined. The vase for dried flowers has an open bottom. Okim makes spoons as well, with bowls with bites out of them.

The prices are surprisingly reasonable for handmade silver. The small spoons start at $45, the middle-sized are $70 and the ladles about $200. Other goldsmiths in the show are Jan Maddox, and Nancy Trimble and the appropriately named Gail M. Goldman. Shopping for Silver

Even with the price of silver, the decline of the hope chest and the said demise of families rich enough to give service for 24 as wedding presents, a great number of couples today are choosing sterling. Many of them use it every day, on the theory that they themselves are as good as the company.

In Washington stores you can find most of the major silver manufacturers. But prices on new silver are changing so fast, you need to be careful. It may be one price when you order it and considerably more when it arrives, warns Dorothy Publiese of Garfinckel's. Safest way is to buy from stock. To add to the confusion, most makers run periodic sales-30 to 50 percent off. But it's hard to say off of what, since the prices fluctuate so much.

Here are a few samples of recent prices (no guarantee they're the same today): Old Maryland Plain by Kirk, six-place setting (salad, dinner forks, soup spoons, teaspoon, butter spreader and dinner knife), $261, a single dinner fork is $54.75, a teaspoon $49; Old Maryland Engraved by Kirk is $314.25. Steiff's Queen Anne is $267 with a fork at $68.67 and a spoon for $35.33.

At Martin's, some patterns are even more expensive. The elegant Buccellati, an Italian handmade sterling, says Mildred Gray, comes in either the larger European size or the smaller American. Prices range from $250 to $600 for a six-piece place setting with forks from $120 to $190. Tiffany is in about the same price range. A handmade silver, Old Newbury Crafts, is carried by both Martin's and Garfinckel's.

As with everything, there are silver discount houses. Fortunoff's in New York is one of the better known. W.S. Bell and Georgetown Silver Shoppe are among the local ones. They sell their wares, according to John Duryee at Georgetown, "about 30 percent off whatever sales prices the manufacturers are currently offering."

Cheaper still are the pieces of used silver, euphemistically called estate silver, "almost antique" as appraiser Duryee says, or simply old silver. Bombe Chest, which supports Jewish charities, and the Christ Child Opportunity Shop, which helps Catholic charities, are two of the better-known sources. Of the two Christ Child seems to have more flatware and complete tea services. But the Bombe Chest carries more in the art moderne style.

The going rate for an old silver fork in good condition and in a pleasant style is about $20- $24, according to Duryee. You'll pay about $4 more for the larger, heavier European size. Spoons are $12 to $16. Expect to pay less if they're monogrammed. Some of the new patterns, being lighter, are less.

European 800 silver, less pure than sterling (but also less subject to being dented or bent), sells for at least 20 percent less, says Duryee. "There's not much market for it." People who have lived in Europe often feel as though 800 silver is a bargain-it looks the same as sterling, it's solid silver, and often it is heavier than the American sterling, meaning that a piece might have just as much silver in it. Silver is usually alloyed with copper, so 800 silver would have 200 parts alloy. Sterling, the standard used in Britain and America, is 925/1000. Coin silver, often used in early American silver, is usually 850. "Fine" silver is the pure metal, not often used because it is so soft.

Mexican silver, also scorned by many, is another good buy. Often it's priced lower than American, but it may even be purer silver. In any case, the workmanship and design are quite handsome. People are now beginning to collect the work of William Spratling, an American who revived the Taxco, Mexico, silver craft.

Chinese and Japanese silver are now beginning to be sought. Some of the decoration is beautiful and the workmanship excellent. Oriental silver is still priced under English, so it counts as a good buy. American silver of the 1870s with oriental motifs are another bargain. They are often delicate and lovely, as contrasted with the heavier historical mish-mashes of the period.

Newspaper want ads are a fine way to find silver-provided you know what you want, take a magnifying glass with you to see the hallmark, and have cash or can talk them into a check. Such sellers are skipping the middle-man's profit. You might even be able to talk them into the silver salvage price. Precious Salvage

Which brings up what to do if your silver was chewed up by the garbage disposal and nobody will fix it. Or perhaps it is a particularly hideous pattern that you hate and nobody will buy. In desperate circumstances there are always refineries who will pay you about 90 percent of the silver commodities price. The refineries, such as Chemicals Metals Industries, Inc., Baltimore, figure their price only on the amount of pure silver in your piece. They melt it down so the process can start all over again.

At a dinner party the other night, an American newspaperman who had served in Hungary told the saddest story. After the war, in a Budapest shop, he'd asked for a cigarette case. "Don't have one," said the jeweler. "But I've just gotten in a batch silver to melt down, I could make you one."

The American asked to see the silver. It was love at first sight, and he bought half of it, all he could afford. Back in Vienna, a friend identified itas belonging to the Esterhazys, an old and royal Hungarian family. Another friend said, "Please let me buy it from you, since I'm on my way home. You go back for the other half."

You guessed it-the friend left with the silver and the shop had already sold the rest. CAPTION: Picture 1, At top are Susan Tamulevich's spoons; Illustration, no caption; Picture 2, the Wilson breakfast room; Picture 3, Komelia O'Kim's decanter and tea service; Picture 4, the table setting at the Woodrow Wilson house; Picture 5 1927 Pyramid flatware; by Margaret Thomas and Douglas Chevalier-The Washington Post; Picture 6, Olaf Skoogfors' candleholders and hallmark; Hallmark photo by Peter Lulleman; Picture 7, no caption; Picture 8, Skoogfor's gold-plated sterling silver pin with blue baroque pearl in the center. Courtesy of the Renwick Gallery