There are people who seem to shimmer in their own heat waves, people who, when shaking a hand, grasp with both of theirs and do not let go. They look squarely into your eyes and, if they like your conversation, may touch your arm or the side of your face; and if they do not, well, they just straight-up tell you. They seem to own the room. And when others look at them with admiration, they own that, too.

Such people find each other, which is why it seemed natural when Graca Machel, freedom fighter, lawyer, and children's and women's rights activist, married Nelson Mandela last year. Last night more than 2,000 people gathered for the annual Africare benefit dinner at the Washington Hilton to pay tribute to Machel, not as the former first lady of both South Africa and Mozambique but as a woman whose passion for changing human lives has made her a hero to many Africans. Mandela was not there last night, but his wife exuded enough magnetism for the whole ballroom.

She is "a tremendous woman who has carried influence, held power graciously, like her name," said Archbishop Desmond Tutu. And then, leaning closer to a reporter, he added mischievously, "They don't know why they succumb to her charm until they succumb."

Africare's Bishop John T. Walker Memorial Dinner, now in its 10th year, has honored former president Jimmy Carter, former Peace Corps director R. Sargent Shriver and civil rights activist Dorothy Height, among others. Unlike them, the 53-year-old Machel only recently began to gain attention in the United States--much of it as a result of her famous second marriage.

Is she overshadowed by her more famous husband? "Mandela, he's an ordinary mortal," former U.N. ambassador Andrew Young replied. "Graca Machel holds her own."

Indeed, she does. Born in Mozambique, Machel studied in Lisbon and fought in her country's liberation struggles against Portuguese colonialism. She became Mozambique's education minister when the country won independence in 1975 and stayed in the post for 14 years, effecting a dramatic increase in the school enrollment of Mozambican children.

In 1975, she married Mozambique president Samora Machel, who died in a suspicious 1986 plane crash.

When she married Mandela, now 81, they became the beloved almost-royal couple that fairy tales and gossip columns relish. Stories abound of the retired South African leader's legendary softness with his third wife, of the way he seems younger and livelier in her presence.

Asked about her accomplishments, including her years as education minister and a recent study for the United Nations on the effect of war on children, Machel deflected the focus to others. "I don't think really this achievement is targeted at Graca Machel. It is a tribute to African women, [and] I have the honor and privilege of giving them visibility."

Yes, but what about you as an individual? "Who am I in this?" she replies. With a meaningful hand-pat, she is done with this line of questioning.

But others have no trouble touting Machel's strengths. Julie Belafonte, singer Harry's wife, recalls meeting Machel for the first time more than a decade ago. "She just bowled me over with her dynamism," Belafonte said. Later, Machel, shimmering in her black sequined top, moved through a sea of tuxedos, ball gowns and kente cloth to a seated Belafonte and talked earnestly, grasping the other woman's hand with both of her own.

Machel is the real thing, said C. Payne Lucas, president of Africare, a nonprofit organization offering aid to 30 African countries. She's so much more than a symbol or a talking head, not your typical wife of a head of state, he said. When you talk to her, he said, "You're not talking to a black African woman. You're talking to a damn woman." This is high praise: His admiration for Machel goes beyond color or politics.

This damn woman, by the way, isn't particularly interested in talking about her husband. When asked why he isn't here tonight, she says simply, "Because he is busy somewhere else." And it seems appropriate. This is, after all, her evening, and what Machel really wants to talk about is how women increasingly are not defined by their male counterparts.

"The major accomplishment [of the past 30 years in Africa] as far as I'm concerned is that today we talk of women's rights, not of women's roles," she says, eager to press the point. Roles, you see, are how others define you. Rights are yours.

This passion is what has made Machel a match for Mandela. "They represent a shared worldview that has transforming power," said the Rev. Jesse Jackson last night. When they are together, he said, "they glow. . . . They give each other vitality."

CAPTION: Graca Machel with Africare founder C. Payne Lucas, center, and R. Sargent Shriver at last night's dinner.