The bull's head is crudely made, cut with the most primitive tools. Looking at it, you can see the Mesopotamian man, about 3000 B.C., hunkered down, carving himself an amulet to protect against powers he couldn't control. He must have worn it often with a string, perhaps made of grass, because eventually, the hole wore through and he had to make a new one. The amulet must have served him well in life and he wore it to his grave.

This poignant piece from a time when mankind had no biographer is one of almost 1,000 objects in "Jewelry -- Ancient to Modern." The glittery galaxy of gems opens Saturday to the public, after a week of preview parties at the Walters Art Gallery, 600 North Charles St., Baltimore. The show continues through Jan. 20.

The catalogue, a magnificent book with 100 splendid color illustrations and more than 500 in black and white, together with informative essays by the various curators will be published as a book by Viking Press in cooperation with the Walters ( $35).

The Walters collection in some holdings, principally the renaissance, is only rivaled by the Metropolitan. This show by no means includes all the Walters jewelry. Another 2,000, including jeweled objects (the Faberge Eggs, for instance), Precolumbian, and oriental jewelry were excluded from the show, though some pieces are visible in other galleries.

Another, more modest show, of gold and silver necklaces, rings and other jewelry, forged, cast, and water welded since 1950 by Irena Brynner, a Russian born goldsmith who now lives in Switzerland, is on exhibit at the Renwick Gallery through Jan. 13.

With today's Rices for gold and silver (see accompanying story on this page), jewelry has become, once again, a big investment. In some parts of India today, women still wear their wealth on their arms, gold bracelets representing all the family's savings. This is a legacy from migratory tribes who once carried their investments in this easily portable form. During periods of great unrest, people in Europe, who thought they might have to flee, frequently put all their wordly goods into diamonds or gold coins. Often it was said you could tell the political climate of Europe by the sale of the Maria Theresa thaler, an Austrian gold coin.

Walking through the exhibit with some of the curators of the show, hearing the stories, seeing the intricately made jewelry boxes, and the paintings on the walls of people wearing the jewelry, it is easy to understand how jewelry has kept its ancient power to protect and charm.

The jewelry of the ancient Near East and that of ancient Egypt, both curated by Jeanny Vorys Canby, begin with the simple stone pieces. Very soon, people had gone to make solid silver armlets. The ancient Syrian (2nd millennium B.C.) gold crowns were put together with hinges held with gold wire. The crowns are worked with repousse (raised decorations). The designs are charming -- flowers and women in one, and women and flower-eating goats in another. A lionheaded goddess wearing a broad collar with twin eagles heads comes from Egypt, 1000-900 B.C.

The Egyptian amulets os snakes and birds are beautiful minature sculptures. A falcon carved of lapis lazuli, and a fish made of sheet gold with silver dorsal fins are especially fine workmanship. A pendant representing Ba, a human head falcon, is made of gold foil. The back is feathers cut of dark blue lapis lazuli, turquoise-colored stone and steatite (soapstone) set into gold cloisons. The pendant is believed to be from the Ptolemaic period, Egypt 400-100 B.C.

At the opposite end of time and size are two works from our own century, so marvelous it is almost impossible to believe they were made in this world and did not grow in a garden of gems on Krypton. The iris brooch 9 1/2 inches high -- was made by Tiffany in 1900. The petals are oxidized silver, set with 120 faceted blue sapphires and ribbed with hundreds of diamonds sparks set in platinum and centered with citrines mounted in gold.

The Lalique orchid comb, made about 1903-04, was carved from a single hunk of ivory. The central vein of the three leaves has a vein of graduated diamonds. The stems are enameled black. The flower is attached to a horn comb so it can be worn in the hair.

The early Art Deco tiger necklace is made of horn carved into stalking cats alternated with tortoise shell cat teeth and claws set in gold.

Henry Walters, son of the founder of the gallery, walked into the Lalique exhibit at the St. Louis World's Fair of 1904. He looked at the orchid comb, the glass and enamel pansy brooch, the opal and diamond brooch and six other fabulous pieces. And he said with a lordly air, "I'll take them all." He paid $1,000 for the orchid, quite a bargain, and twice that much for the glass and enamel brooch.

Walters knew what he was doing. Some 75 years later, Charles Louis Tiffany, his mineralogist, George F. Kunz, and Rene Jules Lalique (the Paris jewelry designer) became the foremost jewelry makers of the Art Nouveau period, the most flamboyantly creative period of jewelry making.

Kunz was a great champion of American gems and he encouraged their extravagant use in the company's designs. The iris, as was the ivory orchid, was a reflection of the Japanese influence, which swept both France and the United States avant design of that period. The Tiffany iris is almost an exact copy of a Japanese painting.

Lalique made a wardrobe of jewels for Sarah Bernhardt. He was a prime exhibitor in Samuel Bing's Salon de l' Art Nouveau . Though his first flower jewelry was made in diamonds, he gradually began to work in glass. After 1909, most of his work was in moulded glass.

In between the primitive near eastern work and the supremely sophisticated Art Nouveau is a wealth of magnificence. Diana M. Buitron, the curator of the Etruscan and Greek work, said that Walters bought most of his jewelry of the period from a single collection, that of Joseph Brummer in 1927.

Buitron in the catalogue points out that Etruscan civilization was at a high peak by 700 B.C. "The jewelry of this period is made with great technical skill, difficult to duplicate even with modern tools." The gold sheet relief pectoral is a 16-inch-wide semicircle, worn on the chest. It was apparently stamped with 10 different designs, including goats (a favorite motif it seems), lions, ducks, humans, leaves, and birds and variations of all.

The Iliad and the Odyssey are full of people being seduced with jewelry, an important use of the objects, Buitron reminds us. And the Herakles knot, often worked into diadems, would heal wounds. In the show is the ancestor of the safety pin, an 8th-century fibula of gold and bronze with three fish cut into the catchplate.

Jewelry even went to the grave with the Greeks. The exhibit shows five fold trappings from a warrior's burial in the last quarter of the 6th century. Traces of mud and reddish deposit still remain on the mask, nose and the diadem. Buitron thinks the gold was discolored because it, along with the body, was burned on a funeral pyre. The mask is slit at the nose, perhaps because the thin sheet of gold was hammered, then pressed over a matrix. The nose is separate, perhaps to keep from harming the dead man's face.

Andrew Oliver Jr., director of the Textile Museum, and a specialist in Greek and Roman antiquities, came over to help with sections on the Olbia Treasure, from South Russia, and Roman jewelry. (During the course of working on the exhibit, he and Buitron were married.)

The Olbia treasure was found in a tomb in the Crimea, on the site of an ancient Greek colony, according to Oliver. A woman's skeleton was marvelously bedecked with two necklaces, two gold rings, a medallion, earrings and a wreath. In her mouth was the gold coin to pay Charon, the Styx ferryman to the underworld.

The gold was sold, by the peasants who found it, to a Moscow collector who was told by archaelogists that the pieces were not authentic. The Moscow man sold them to a London dealer with the fine name of Spink. J. P. Morgan bought some pieces now in the Metropolitan Museum and the Wadsworth Atheneum, Hartford.

Walters bought the butterfly necklace, set with emeralds, and colored glass and stone in the Hague, with some other gold ornaments alleged to come from Olbia. Oliver says its impossible to say whether all the objects really did or not.

The pair of 1st century Greek jeweled bracelets are splendid objects, though some of the stones are modern replacements. The gold arms are decorated with floral and leaf designs of gold enamel.

Oliver, in the catalogue, points out that Pliny said in 300 B. C. in Rome: "A woman could wear no more than half an ounce of gold; and only senators and knights were allowed gold rings." But after the Pompeian victories at the turn of the 1st century, the rules were relaxed. We have a good idea of how the jewelry was worn from the mosaics and wall paintings in Pompeii and Herculaneum.

The gold lion bracelets are especially interesting. One bracelet had two lion heads biting the sides of a ball -- unfortuantely, one lion was lost. Many rings and bracelets were in the shape of a serpent, a favorite form.

Richard H. Randall Jr., the director of the museum, curated the migration, Byzantine and medieval jewelry parts of the exhibit. He points out that the two greatest Visigothic eagles in the world are in this collection. The Visigoths were a tribe that migrated from south Russia to Spain, after adventures in Romania, Greece, Italy and France. The eagles are fibulae, safety pins, made of bronze overlaid with sheet gold and inlaid with garnets, a cabochon (rounded top) crystal, colored stones, and an amethyst eye.

Carnelians set in gold formed a garniture, which Randall believes was the chamfron of a horse.

"Most of the jewelry was made for the men of the tribe. They used it to keep their clothes on," Randall said. A gold arm torque, he pointed out, was the sort of thing they put their money into so they could keep their savings with them when they shipped out.

In the Byzantine group, Randall pointed out a 16th-century gold pendant with its sacred relic of the true cross. The cross fits into a case and the back, set with a amethyst cameo and other precious stones fit over it. An ancient joke is a gem, carved with the likeness of that most pagan of golds, Pan, set in a ring inscribed with the 16th psalm. Randall thinks a gold ring decorated with eight scenes of the life of Christ in minature is extraordinary.

Randall said that medieval men and women had an elaborate pharmacopeia involving stones. A sapphire protected you from injury, fraud and terror; the green toadstone cured dropsey, and the amethyst prevented drunkeness. One inscription, AGLA could translate, "Thou art mighty for ever, oh Lord." It could also mean, "I am love and the gift of love." Randall suggested that if the recipient's name was Anne, it could mean something else again.

The renaissance section was curated by Diana Scarisbrick, but I went through the exhibit with Mary Smith Podles, now the renaissance art curator. Podles pointed out the Esterhazy marriage collar, made in Hungary in the early 17th century. It was made for the groom, Palatine Miklos Esterhazy to wear at his marriage in 1611. The 14 gold sections are set with rubies, diamonds cut in pyramidial and triangular shapes, and pearls.Podles pointed out the symbols, the clasped right hands, the parrots of peace, the doves of love and the cornucopiae of prosperity worked into the necklace.

Many of the other renaissance pieces are pendants. Podles said that master designers made engravings of their best pieces. The engravings were then sold all over Europe. So the goldsmith in England might buy the engravings from a designer in Holland, and then vary the formula to fit his client. Much of the work seems derived from Benevenuto Cellini. Some of the pendants were really perfume holders. And one was made to be a teething ring (a chain fastened it so it couldn't be swallowed.

A marten's head, probably from Venice, was used to hold together a fur piece. A ruby is set between the black enamel eyes and grapes are being eaten by black ducks on the knotwork. The ears and collar are set with rubies and seed pearls. The tongue and white teeth are hinged and could come out.

The catalogue points out that many of the grotesques had their inspiration from the underground grottos of Nero's Golden House on the Esquiline.

Wandering among all these jewels makes you feel opulent, as though for that space of time you were some great Medici in his treasure house.