BERKELEY -- A lump of almost pure gold residing at UC Berkeley's Bancroft Library is believed to be the original nugget whose discovery launched the California goldrush one and a half centuries ago.

To mark the 150th anniversary of the famous gold find, the original nugget is once again center stage, this time for Bay Area schoolchildren who are learning that the best way to study history is to experience it.

On Thursday, Jan. 15 at 11:00 a.m., fourth graders from Fruitvale Elementary School in Oakland will visit UC Berkeley to see the nugget first hand and learn California history from UC Berkeley's specialists. The Fruitvale students are among 450 children invited to view California historical treasures this month at The Bancroft Library, which holds what is likely the world's largest collection of original California documents and manuscripts.

Every child in the Golden State studies goldrush lore in fourth grade. They learn that more than 80,000 people hurried to the then sleepy town of San Francisco in a single year, hastening statehood for California, and that nearly $2 billion in gold was ultimately taken from the earth. Even so, few Californians struck it rich in the boom. Wiser immigrants turned to farming and supplying miners with high-priced goods and ultimately settled Northern California.

The Fruitvale children are receiving a tour of the materials from The Bancroft collection through a UC Berkeley program called the Interactive University. The Interactive University is the technology arm of the Berkeley Pledge, a program designed to enrich learning for disadvantaged youths from four Bay Area school districts. The Interactive University and its partners* have made available over the Internet more than 28,000 digital images and manuscripts online in The Bancroft Library's California Heritage Collection, which is funded by the National Endowment for the Humanities. Fruitvale Elementary and many other schools in the Bay Area use the images in history lessons.

However, "when people see things online, then they know they exist," said Lisa Yesson, project coordinator for the California Heritage Collection. "Then they want to see it in person."

The Bancroft nugget was the first of several pieces of gold collected by James W. Marshall and Peter L. Wimmer, sawmill foreman at Sutter's Mill, along the American River at Coloma where gold was discovered on Jan. 24, 1848.

In documents accompanying the nugget, Wimmer's wife writes, "They picked up a nugget of metal and Mr. Wimmer sent it to the house to me by our son and I boiled it in a kettle of soap all day to test it to see if it was gold. It proved to be a nugget of gold. From that the mining began."

Marshall afterwards took the gold piece weighing a little over a quarter of an ounce along with other samples he had discovered to Fort Sutter and "had it tested with acids and proved it to be pure gold," wrote Elizabeth Wimmer. She writes that Marshall presented her with the nugget as a memento of the great discovery and she carried it in a leather bag around her neck for the next 40 years.

Subsequently it passed to San Francisco attorney W. W. Allen and Chicago collector Charles F. Gunther before The Bancroft acquired it in the 1950s and brought it back to California.

Sometimes called "the Wimmer nugget," it is likely one of the larger pieces of gold collected on the day of discovery, another smaller flake being in the Smithsonian collection.

Before UC Berkeley acquired the nearly one-inch long Wimmer nugget, it was exhibited as "the original nugget" at the California State Fair in 1892 and in the California building at the Chicago World's Fair in 1893.

Besides goldrush history, the Fruitvale children visiting UC Berkeley will study the 1906 earthquake and original family papers from The Bancroft collection.

"When their teachers came to campus, they felt the personal experience here at The Bancroft was so powerful," said Yesson. "Although technology has made a lot of things possible, there is still a lot to be gained from the in-person experience."