BOOK REVIEW / NOVEL : Writer Spins Soap Story Into Pure Gold : LIMESTONE & CLAY: <i> by Lesley Glaister</i> ; Atheneum $19, 185 pages

If you first encountered “Limestone & Clay” through a plot summary, you’d likely be disappointed. Much of it is awfully familiar: the woman who longs to bear a child, her jealousy of a pregnant acquaintance, her guilt about ancient family incidents, her anger at a lover’s foolhardy, relationship-threatening hobby.

Indeed, the novel’s central couple seems almost stereotypical, right down to their metaphorical identification in the title: Simon, a geography teacher and cave-explorer, is limestone, while Nadia, a skilled potter, is clay.

Lesley Glaister is a fine writer, however, and it’s soon clear that Limestone & Clay won’t degenerate into movie-of-the-week banality. After awhile, in fact, you wonder how Glaister can get so much out of rather predictable material; in the hands of a commercial writer, the novel would approach parody.

That never happens here, though, for Glaister--whose first novel, “Honor Thy Father,” won Britain’s Somerset Maugham Award--has immense sympathy for her characters, even when they do silly and spiteful things.

Nadia is already depressed when the book begins, fallow in both her creativity and her body, but things get worse when she learns that Simon’s old girlfriend, Celia, is pregnant. The pain becomes almost unbearable when Celia tells Nadia, punishingly, that the child is Simon’s, Celia having persuaded him to act as a sperm donor because her husband had had a vasectomy.

Nadia, desperate, leaves home before Simon arrives, spending the night in a hotel where she ends up baby-sitting--and miraculously nursing--an infant. Simon is irritated when he discovers Nadia gone and determines to find, alone and at night, an uncharted passage linking two caves . . . and where his friend Roland died, years before, on the same quest.

The novel has all the makings of a two-part soap opera episode. But Glaister exploits the material not for effect but for illumination, showing us not confrontations between characters but individual, internal reactions to strife.

Nadia hardens herself against Simon, wanting to kill him, or even his gestating child: “Death seemed the only possible remedy for the anger she feels. Murder. The shock of absolute cold to quench the flames.”

Simon, en route to his pioneering adventure, thinks of Nadia’s skepticism toward his caving: “For glory, Nadia would say, a sneer in her voice, as if glory was a petty thing, a paper rosette to pin on your chest. There would be a sort of glory . . . but glory wouldn’t be the main thing. Not the nub of the achievement. That would be personal.”

Celia rues, if only slightly, her thoughtless cruelty toward Nadia: “It was reckless, like tinkering with an experiment, shoving an extra element into a test tube and then regretting the fizzy coloured flare.”

Simon and Nadia endure individual crises, naturally, during the night they spend apart. Nadia’s does not derive from her unaccountable ability to produce milk, however; she drinks too much, finds dealing with the baby difficult, and ultimately drops the child on the bathroom floor. It’s a horrifying scene, because we know what mixed feelings Nadia now has toward children.

Equally horrifying is Simon’s experience in the cave, where his indignation and pride drive him ever onward, hoping to find a way through until he is wedged, exhausted and in total darkness, in an impassable corridor. He falls into unconsciousness, inches from Roland’s bleached skull.

If there’s a flaw in “Limestone & Clay,” it’s the unexpectedly optimistic ending. The deaths for which Glaister has set the stage are narrowly averted. And although Simon and Nadia are both changed by events, they are nonetheless willing to try to pick up the pieces of their relationship. Simon quits his job; Nadia regains hers.

“Limestone & Clay” may be a bit too sanguine in the end, but it’s certainly a good read. It’s also a textbook example of the alchemy practiced by good writers: turning common straw into lasting, elemental matter.