The earliest known piece of jewelry that Danish silversmith Georg Jensen (1866-1935) made to his own design was an “Adam and Eve” belt buckle (1899). The cast silver and gilt-silver buckle, roughly 4 by 6 inches across, depicts Adam and Eve flanking the tree of knowledge in the Garden of Eden, a scene framed by the long body of the serpent. It is one of nearly 400 examples of jewelry, hollowware, sculpture, and archival material in the stunning exhibition “Georg Jensen Jewelry” at the Bard Graduate Center.

The belt buckle is heavy and deceptively crude in places. It recalls Romanesque stone carving on church capitals, Nordic wood-carving, and Hiberno-Saxon jewelry from the migration period. Its story springs forth clearly and straightforwardly, as if it were a masterful illustration from a children’s book.

Adam is planar, solid, and heavy-footed; he is both childlike and masculine, as if roughly hewn from wood. Exposed and expectant, he steps toward Eve with outstretched hands. Eve, liquid and sinuous, reaches up and picks the fruit from the tree. Her arm is thick and scaly, and her hand, wide-open and clasping the fruit, looks as if it had transformed into the mouth of a snake.

Her other arm, equally lithe yet demure, slithers down from her shoulder to below her waist. Like her long ponytails, which slide down and cup her breasts, her arms appear to continue the movement of the serpent, whose long, broad body is the frame, ground plane, and intruder of the scene. Its large head drops threateningly down between the two figures; its long forked tongue touches their shoulders. Perched as it is above the branches, the snake’s head transforms the tree into the serpent’s standing body; its leafy branches into swallowing arms.

The buckle appears to have little in common with the belt buckles Jensen would produce only five years later. It is nothing like the Neoclassic naturalism of Jensen’s later jewelry; nothing in Jensen’s own designs reaches again toward illustration. Yet Jensen’s simple treatment of Adam and Eve includes everything essential to the designer – his love of symmetry, frontality, and restraint, as well as his lifelong commitment to the art of the past and to sculpting natural forms and nature’s rhythms.

In Jensen’s mature work, forms clasp together like butterfly wings. Thin and wavy silver leaves, birds, filigree, and flowers flow like water over shallow stones. Semiprecious gems cluster like seed pods, drop like tears or berries, and glint like reflections on water. His flora and fauna, though literal – dragonflies, doves, vines, flowers – quickly rise to become the best kind of decoration: A decoration that no matter how regal never becomes ostentatious; no matter how ornate never becomes busy; and no matter how overt never loses its primary sense of inwardness, naturalism, and restraint.

“Georg Jensen Jewelry,” the first comprehensive retrospective devoted to the jewelry of the Georg Jensen Company, focuses mainly on the work of Jensen himself. But it covers the period from the founding of the company in 1904 to 1973, when the Jensen silversmithy was sold to Royal Copenhagen. Thus it includes sections devoted to Jensen’s predecessors, mentors, influences, and peers, as well as to the company’s star employees – many of whom worked after Jensen’s death.

Arranged chronologically, “Georg Jensen Jewelry” begins with early jewelry, earthenware vases, and the plaster bust “My Father” (1887), which Jensen submitted for entrance to the Royal Academy of Fine Arts. Trained as a brazier in a knife factory and, later, as a goldsmith and a ceramist, Jensen taught himself to sculpt and always considered himself a sculptor.

The show’s section of early works – which includes “Maid on the Jar” (1899), an earthenware pitcher whose handle rises into the figurehead of a woman who stands on the lip of the jug – are all very accomplished. But their Protestant stoicism and academic leanings do not prepare you for the nonstop burst of genius and creativity that begins in 1904. The bracelets, brooches, pendants, earrings, flatware, and hollowware made by his company defined nearly every design movement from the late 19th through the late 20th century, even as they transcended them.

Jensen knew how to transform metal into breathing, writhing form. He knew what materials to use when and in what amounts. And he used them all: silver, lapis, coral, agate, amber, tortoiseshell, moonstone. Just when you think his understated temperament cannot handle going for broke, a piece like “Necklace” (1914), a foot-long explosion of silver leaves, opals, turquoise, and enamel, proves you wrong. Just when you think he could not handle the barbaric sparkle of diamonds, emeralds, black opals, and gold, “Ring, design #201” (1920) and “Pendant” (1925-30) – intricate rococo affairs – show he could.

At the end of the show are many works by other Jensen Jewelry designers. Jensen’s company internalized, embodied, and renewed the Arts and Crafts movement, Art Nouveau, Art Deco, Biomorphism, and Proto-Functionalism, and the exhibition gives us a beautiful overview of some of the high points of jewelry design from Victorian to Pop.

We see brilliant designs by artists such as Harald Nielsen, Arno Malinowski, Astrid Fog, and Bente Bonne. There are beautiful icons such as Malinowski’s “King’s Emblem” (1940), a pin that became a symbol of Danish resistance during the Nazi occupation of Denmark; Henning Koppel’s magnificent “Bracelet, design #88” (1946), a string of silver forms that resembles a flock of birds; Nanna and Jorgen Ditzel’s “Bracelet, design #107” (1954), nicknamed the “Axe” after the Viking tool; Bent Gabrielsen’s “Brooch, design #385” (1971), an abstract splash of silver; and the Calder-mobile-inspired “Necklace” (1951-58) by Vivianna Torum Bulow-Hube (an artist Picasso adored).

These works provide a much-needed and refreshing change. Yet some of these later designs, despite their simplicity and beauty, feel unnatural or too pared-down. Their understatement is overstated. In short, they lack Jensen’s organic naturalism, invention, and breadth – the very things that give his sculptures and jewelry not the qualities of design but those of life.

Until October 16 (18 W. 86th Street, between Central Park West and Columbus Avenue, 212-501-3023).