It's all over for the Osmond dream couple. Singer Marie Osmond, whose marriage was the envy of so many mothers, sued her husband Steve Craig for divorce yesterday. They had been married for three years and had made several unsuccessful attempts to reconcile their differences. They have a 2-year-old son . . .

Marvin L. Stone, who retired this year as editor of U.S. News & World Report, will be nominated to become deputy director of the United States Information Agency, the White House announced yesterday. Stone was with the news magazine for 25 years, nine of them as editor . . .

Washington Post sports writer William Gildea has won first prize for feature writing in The Sporting News' annual competition for Best Stories and Photos. He won for his three-part piece on a cross-country baseball odyssey with his children that will be reprinted in the anthology. Other Post writers who will be represented in the book are Thomas Boswell, John Ed Bradley, Ken Denlinger, John Feinstein, Jane Leavy, David Remnick and Michael Wilbon . . .

When Calvin Rensberg, who plays Old Deuteronomy in "Cats," came onto the stage to sing at Monday night's Helen Hayes Awards, a voice from backstage announced he started his career at Fort Hunt High School. He graduated in 1968 from the Fairfax County school known nationwide for the successes of its band and other music departments. But at the end of this semester, the school will cease to exist. It is being closed because of enrollment declines in the eastern part of the county . . .

As the Claus von Bu low trial continues, a chemist testified yesterday that a needle allegedly owned by von Bu low had so high a concentration of insulin it was "off the scale." Von Bu low is charged with trying to kill his heiress wife Martha (Sunny) von Bu low with insulin shots. She is in an irreversible coma in a New York hospital . . .

Peripatetic oilman Armand Hammer has given away some more money. This time the Metropolitan Museum of Art in New York will receive $1 million toward the renovation of the museum's Equestrian Court, which houses the popular cavalcade of "Knights in Shining Armor" . . .

There was a plan under way in President Reagan's boyhood town of Dixon, Ill., to honor him by building an arch over the city's main street boasting that the town was where the president grew up. That plan did not carry. The arch will instead honor veterans . . .

A state jet carrying Florida Gov. Bob Graham suddenly depressurized and went into a two-mile dive on Monday. While the staff aides were a bit unsettled, the governor, they claim, went on with his paperwork as though nothing had happened . . .