Queen Noor al Hussein, "the light of Hussien" -- the fourth wife of the ruler of the Hashemite Kingdom of Jordon and convert to Islam -- looked up at the welded Tony Caro sculpture perched above the central courtyard of the National Gallery of Art's East Building.

She turned to Gallery Director J. Carter Brown and said, "I was welding sculpture myself at the university -- but I never reached any peak of excellence."

It was the kind of remark to remind one that Queen Noor, 28, was once Lisa Halaby, the blond, Washington-born architecture graduate of Princeton University. She has retured to Washington for a state visit with her husband, King Hussein -- her first trip back since she left two years ago for Jordan and her wedding.

"It looks very green," she said of the city in her deep, clipped voice, "especially coming from a more parched environment."

Later, at lunch, her younger sister, Alexa, sitting a table away from the queen in the John Quincy Adams Room of the State Department, looked at her and said she didn't look any different than she had two years ago. But yesterday, she looked well, regal.

Her schedule included a morning tour of the East Building conducted by the director, and the 12:30 State Department luncheon hosted by Jane Muskie, wife of the secretary of state.

The queen arrived -- smiling -- by limousine at the National Gallery. She was tall enough to tower over the other women -- mainly wives of diplomats, as well as Kit Dobelle, director of Rosalynn Carter's staff.

Queen Noor is more striking than beautiful -- exquisitely dressed, exquisitely calm, smiling easily, clasping her hands in front of her. For the morning tour, she dressed in a perfectly color-matched ensemble: a purple crepe blouse tied at the neck, with purple crepe pleated skirt and a double-breasted purple printed jacket. Her shoes were purple high heels. Her purse was purple. Her hair was pulled back rather stiffly into a bun, on which were a thin purple headband and a tiny purple bow. Her purple-and-pink earrings matched a bracelet and ring and she wore a diamond bracelet as well.

"Anything she wears fits her," said her friend, Nawzad Ben Shaaker, the wife of the commander-in-chief of Jordan's armed forces. "She has the allure in her."

Everywhere she went, people stared. In the museum, women in jeans and jogging shorts gave her slow once-overs in near-astonishment.

Brown took the queen all over the gallery, animatedly explaining the history and anecdotes behind the art -- a Calder mobile here, a van Gogh there, the Islamic influence in Matisse. He went to some length to talk about the architecture of the East Building, and later loaded the queen down with pamphlets and catalogues about the gallery -- she is particularly interested in museums as educational facilities.

"She's interested in art and architecture and trying to help in various things being done in Jordon," said Patricia Veliotes, wife of the American ambassador to Jordan. She paused for a moment. "I don't think we ever talked about Washington and life here."

At one point, the queen suddenly stepped back from one of the paintings, unaware of other people around. She turned to Kit Dobelle and told her she didn't want to crowd the art and spoil other people's visits.

At the end, she thanked Brown for the tour and gave him a standing invitation to come to Jordan. Outside, in front of the building, she stooped to her knees, skirt trailing the ground, to play with a visitor's stroller-bound child.

The queen has brought her own infant son, Prince Hamzah (and his nanny), to Washington. "He's a perfect combination of his parents," said Alexa Halaby enthusiastically about the nephew she visited in Amman last month. "He has his father's calm. He's very serene. And he has his mother's gay eyes. He looks at everything, nothing escapes him. And he loves an audience." Queen Noor has taken pictures of King Hussein and his son lying on a bed making faces at each other.

At the State Department luncheon, when Jane Muskie stood to give a toast to the queen, she referred to her as "Your Majesty."

"We call her 'Sitti,'" said Nawzad Ben Shaaker. "It means my lady.' This is a term we use to address all queens -- if we know her on personal terms."

According to Alexa Halaby, the queen can speak and write Arabic.Said Ben Shaaker, "We speak English most of the time. She doesn't seem like an Arab. But she does seem like an international person whom we can get along with. I call her a breath of fresh air."

For the luncheon, Queen Noor had changed -- "very quickly," she said with a grin -- to a beige suit with a huge jeweled brooch and black patent-leather shoes."I hope there will be many more trips," Queen Noor said to the group. "Both ways I hope many of you will come and see what our country's about and learn a little about us . . . I know our good relations will be continued." With champagne glass raised, she toasted "Mrs. Muskie, the U.S. and peace for all mankind."

Among the guests at the queen's table were her mother, Doris Halaby, and Marvin Sadi, director of the National Portrait Gallery. "We talked about her husband's portrait and who would paint it," said Sadik.

"I suppose she misses friends," said Alexa Halaby, who still calls her sister Lisa in private conversation. "But she has her own life now in Jordan."