Except for the urns, it had the ingredients of any Washington ground breaking: a packed dais, a huge white tent, military band and restless audience. But the crowd of 500 soon fell silent yesterday morning. As the music of the haunting Jewish prayer "Ani Ma'amin" ("I Believe") began, Holocaust survivors opened six small containers and poured gray-brown silt, ashes and earth from Nazi death camps and their victims onto the American soil that will hold the United States Holocaust Memorial Museum.

As the fine dust and clots of dirt fell, many in the audience -- e'migre's and survivors, Jews and gentiles -- began to weep. Under the serene autumn sky, the tented gathering on 14th Street took on the feel of both a wake and a celebration. Eyes closed with the weight of gratitude and grief.

"Come and see," Holocaust survivor Elie Wiesel urged in his speech. "Come and learn what human beings can do to other human beings. Learn the limits of humanity. Learn, and hope is possible. Forget, and despair is inevitable."

The museum is to be built with private money on federal land one block from the Mall. When it is finished in 1988, it will be the only national Holocaust memorial outside Israel, and a message to the gathering from President Reagan yesterday alluded to controversy over its location, design and conception that began soon after the memorial was first proposed in the late '70s.

"Although some have questioned the wisdom of placing the memorial for a European catastrophe so close to the gleaming symbols of our democracy, the lessons of the Holocaust . . . do belong here," the Reagan message said.

"Today much of the world still struggles to rid itself of the rule of godless tyrants and murderers. This memorial will stand always to remind us of the nobility of that struggle and the perils if we remain indifferent."

Reagan's message was read by Interior Secretary Donald Hodel, who joined Senate Majority Leader Robert Dole and House Majority Whip Thomas S. Foley in voicing enthusiastic support for the memorial. But it was Wiesel's emotion-charged voice and stark words that most moved the crowd in the moments before the urns labeled Auschwitz, Bergen-Belsen, Dachau, Theresienstadt, Treblinka and the Warsaw Jewish Cemetery were emptied.

"This museum is not intended to awaken hatred nor separate people," Wiesel said. "Quite the opposite: It is meant to bring people closer together. Faced with our memories, the visitor will have no choice but to become more sensitive to his or her fellow being's suffering.

"One day a child will stop here and ask, 'Father, what is this building about?' . . . And the father will say, 'In those times the angel of death had many allies.' 'Why?' the child will say. 'I don't know,' will be the answer.

"In this place," Wiesel said, "we will try to say what, but we cannot tell you why. Why Treblinka? Why Auschwitz? Why the indifference of so many leaders? Why the story had to occur. Only God has the answer, but in the case of 1 million children, the answers become questions . . . The killer killed his victims once, and there is nothing on earth that we can do about it. But, if they are forgotten, they will be killed a second time, and this we can and must prevent."

In addition to critics who question the need for a memorial or its placement on the Mall, there have been those who said they feared the memorial would emphasize the Nazi extermination of 6 million European Jews to the exclusion of other victims.

The museum's council, appointed by President Reagan, has worked to give the memorial museum a universal quality and yesterday's speeches continued that effort. An invocation by the Rev. John T. Pawlikowski, a member of the memorial's advisory council and a Roman Catholic priest, mentioned "Slavic, Romani, gay and handicapped victims of the genocidal attack on fundamental human dignity."

Wiesel's speech referred to "oppressed, tormented, persecuted, imprisoned and executed French heroes of the Resistance, Yugoslav and Greek and Russian partisans, Ukrainian peasants, Bulgarian and Polish patriots, Dutch workers, Belgian students, Norwegian intellectuals, Danish policemen, German and Austrian anti-Nazi militants, Italian anti-Fascists, Czechoslovakian freedom fighters."

At least one group was left off the list and felt slighted. John Buckley, Washington spokesman for Jehovah's Witnesses, said after the ceremony an estimated 6,000 to 10,000 German Jehovah's Witnesses were imprisoned in concentration camps by Hitler for their refusal to fight for Nazism.

"It appalled me that they would mention every group under the sun and leave out Jehovah's Witnesses," Buckley said, adding that Wiesel had apologized for the omission and described it as an oversight. The Jehovah's Witnesses are one of many groups at work on research to be included in the memorial's exhibits and archives.

Other speakers used the occasion to warn about present-day dangers like terrorism, citing the recent murder of American tourist Leon Klinghoffer at the hands of Palestinian pirates. One woman in the audience said afterward that she was disappointed South African oppression hadn't been mentioned.

The memorial's citizen board has raised more than $21 million, and pledges for that much again, of the $100 million needed to build, staff and endow the memorial. When finished, it will include a Hall of Remembrance, a Hall of Witness for exhibitions and an educational section for library, archives and auditorium. Council members said yesterday donations have been received from Jews and non-Jews alike. The Rev. Robert F. Drinan, a Roman Catholic priest, former congressman and professor of law at Georgetown University, said after the ceremony that he would like to see Catholic churches around the country set aside one Sunday to raise money for the memorial.

Memorial planners once had hoped to use the site's original brick buildings because they reminded some council members of the barracks at Auschwitz. The buildings have since been razed, however, in favor of a new design that council members say will permit more efficient use of the lot on 15th Street SW, south of Independence Avenue.

Some schoolchildren in the audience chattered as they left the tent, but many of the elderly appeared miles and years away. A Czech e'migre' who now lives in Bethesda made his way up the tent's center aisle. He knelt on one side of the small square of ground visible through a hole in the artificial-turf tent floor. His wife, Alice, kneeled on the other side and as she touched the dirt with her fingers, he snapped a picture.

When a reporter asked him about the ceremony, his eyes filled with tears. When he was able to speak, he explained that his grandfather had been killed at Auschwitz; his wife had lost her parents, grandparents, aunts and uncles there.

"It has affected our lives and our children's lives, yet there are still those who say it didn't happen. This says it did happen . . . it could happen, and not just in some exotic, faraway place.

"It hurts," he said, gesturing at the brown patch of earth. "But it would hurt more if there were nothing."