In many ways, the roughly eight-inch-wide stained-glass and metal shard has always acted as a symbol of what the Jimerson family stood for. It rested on a hutch in the dining room and traveled with the Jimersons as they left the deep South. Melva Brooks Jimerson would take it to women’s groups and Sunday school classes when she was invited to talk about the family’s years in Birmingham, Ala., and people would go tearful or silent; or they gasped.

Her husband, Norman “Jim” Jimerson, was a white Baptist minister who worked on racial issues, and he handled it most that first day, Sept. 15, 1963, when he drove to the site of the 16th Street Baptist Church and picked through the rubble for some symbol of what, incomprehensibly, had just happened — four girls, taking a break after Sunday school, had been killed by a bomb planted near the basement of an African American church.

It was arguably the most emotionally shattering event of the civil rights era.

Monday, four of the five Jimerson children will be in Washington to donate the glass shard to the Smithsonian National Museum of African American History and Culture, which broke ground in February 2012 and is projected to open in 2015. The shard will join a few smaller pieces from the bombed-out church already in the museum’s collection. It has been nearly 50 years since the explosion that killed Denise McNair, 11; Carole Robertson, 14; Addie Mae Collins, 14; and Cynthia Wesley, 14. Dozens of others were injured, and two black teenage boys died in the bombing’s violent aftermath.

Artifacts from the day are rare, says the museum’s director, Lonnie G. Bunch. And “so unbelievably important.”

“In many ways, this bombing was a moment that the world would never forget,” Bunch says. It came within a month of the March on Washington, and it “reminded us that there is not change without loss, and the loss was so poignant because they were so young.”

It is also a reminder that while a “majority of people in the civil rights movement were African American, there were a significant number of white Americans who basically said: This is my issue, too,” Bunch says.

The tangible past

The glass retains its vivid orange, blue-green and yellow hues, and it is framed by twisted and traumatized pieces of metal. “Twisted like the minds that caused it,” Ann Jimerson, a health communications specialist who lives in Tenleytown, remembers her mother used to say. Ann, who was 12 at the time of the bombing, says that decades later the shard is still beautiful. She is struck “by the richness of it. The oldness of it,” Jimerson says. And by what it meant to her and her family. “We were on the right side,” she says. “It was wonderful to be so clear.”

That clarity came at a cost.

Randall Jimerson, an archivist and history professor at Western Washington University who lives in Bellingham, was 14 at the time of the bombing. The family, he says, was inspired to donate after hearing President Obama talk at the museum groundbreaking about how it would house artifacts that would help his daughters understand the civil rights era. “He mentioned specifically broken shards of glass from the 16th Street Baptist Church,” Jimerson says. His voice breaks, and he pauses. “When I heard that, I said that’s what we have to do.”

The Jimersons — who include two more brothers, Paul and Mark, and a sister, Susan — were New Englanders who moved to Alabama when their father began working as director of the Alabama Council on Human Relations. He was called a communist, and the family was disinvited from two churches. A vocal number of whites bitterly resisted desegregation, and a spate of bombings from the 1940s forward had earned the city the nickname “Bombingham.”

The Jimersons had returned from church when they heard news on the radio of the bombing. Randall recalls his father asking white ministers to go with him to the black community to show support that day, but everyone declined. His parents drove to a gathering at a home where Martin Luther King Jr. often stayed. Then his father drove to the church, where he picked up several pieces of glass.

In the bombing’s aftermath, Johnny Robinson, 16, was shot by police, and Virgil Ware, 13, was shot by two white teenagers. Jim Jimerson attended funerals for all six people who died, and he spoke at the funerals of the two boys. One member of the Ku Klux Klan was convicted of the bombing in 1977; two others were brought to trial later and convicted in the early 2000s. Two additional suspects implicated in an FBI memo died without being charged.

The Jimerson family donated a piece of the church glass to the Birmingham Civil Rights Institute in the early 2000s. Donating this piece to the Smithsonian brings back the tensions of the era but also “feelings about the importance of the work our father was doing,” Randall Jimerson says.

“I’m in tears now, talking to you about it. Tears of what I’m not quite sure. . . . I think it just brings back all of the emotions of what we went through during those times.”

In a forthcoming book, “Shattered Glass in Birmingham: One Family’s Fight for Civil Rights, 1961-1964,” Jimerson writes about a teacher yelling at him when a civics class discussion turned to civil rights. And a classmate, using profane language, asked him whether he loved blacks:

“I paused for a moment or two, and as the bell rang to begin class, I finally said, ‘I try to love everyone.’ . . . That’s the only answer I could give to his question.”

Suffering for the cause

It is perhaps a second tier of civil rights emotion that the country is just starting to get to — the disaffection and alienation felt by families like the Jimersons. Whites who worked for black equality during that era paid a price, and it wasn’t just levied by the cross burners and assassins. It was levied by good white people who saw other good white people taking a stand against racism, one they couldn’t match. So they shunned or name-called.

Randall Jimerson says he was always surprised that they didn’t have crosses burned in their yard. As a teen, he said, he almost would have welcomed that kind of dramatic proof that they were fighting evil. “Instead, we just got death threats on the phone and social ostracism,” he says. And if the topic of desegregation came up, it could spell the end of a friendship. “It was almost like a ‘don’t ask, don’t tell’ policy.”

He says he doesn’t compare his experience to the injustice and brutality that blacks experienced, “but in a small way, it took a lot of courage for white people as well to be part of the civil rights movement.”

When Ann Jimerson started a Web site about kids in 1963 Birmingham, she reached out to Freeman A. Hrabowski III, president of the University of Maryland Baltimore County. He grew up in Birmingham, was a member of the Sixth Avenue Baptist Church (sister church to the 16th Street Baptist Church) and was a classmate of bombing victim Cynthia Wesley.

The Jimerson donation reminds him how touched he had been to see all the white faces at those Birmingham funerals. He calls the donation “a wonderful moment to remember that there are so many good people across the races” who have always been in the struggle.

In the middle of the biggest U.S. social upheaval of the 20th century, Ann Jimerson says their family carried around the “ark of the covenant,” the table and hutch that contained the glass shard. They moved every few years — Michigan, New York, Massachusetts, Virginia — but the glass was always there, reminding them of the violence of hatred. And sometimes the aching loneliness of what it meant to be on the right side.