Gem Exhibit a Cut Above : Museum: New mineralogy display engages patrons in show of area’s mining history.

If you think the San Diego soil is good only for supporting manzanita and condos, think again. Under your feet is a virtual Tiffany’s.

“San Diego mines are the largest producers of fine gemstones in North America,” said Michelle Fortier, spokeswoman for Balboa Park’s Natural History Museum. “A lot of people don’t realize the kind of resource we have.”

Topaz, gold, silver, kunzite, garnet, quartz, aquamarine, tourmaline--all have been mined here since the first recorded gem discovery in 1876 by a Pala Indian. Tons of local pink tourmaline, a favorite of the empress of China, even found their way into the Forbidden City.

Although a century of mining has exhausted most claims, many significant mines remain in the Pala and Mesa Grande areas of Northern San Diego County.

That’s why museum officials spent four years and close to $400,000 on the new Josephine L. Scripps Hall of Mineralogy--a 3,000-square-foot permanent exhibit opening today that they hope will not only educate, but dazzle.

Visitors can take armchair field trips anywhere in the country, learn why gems sparkle, even test radioactivity.

“This is going to be one of the most innovative exhibit complexes in the country,” Fortier said. The reason, museum officials say, is the emphasis on interactive displays.

“Most museums display their minerals in cases that have them lined in neat, orderly rows,” said William Estavillo, chairman of mineralogy.

“They may be very beautiful minerals but they’re generally very boring exhibits. . . . What we wanted to do was have (visitors) able to interact and relate with the properties of minerals, especially with the more spectacular ones such as fluorescence, magnetism and radioactivity.”

Where, for example, outside of a “Simpson’s” cartoon, could you play with a little uranium? The Radioactive Rock exhibit lets visitors use a Geiger counter to measure how well materials such as concrete, wood and lead block radiation. Those concerned about how well the exhibit blocks radiation need not fear, Fortier says. “You’d have to spend 500 hours in front of (the exhibit) to feel the effects of an ordinary chest X-ray.”

Another hands-on display uses a laser to demonstrate why gems sparkle. Yet another shows the effect light has on a gem’s color.

And Touchstones, an exhibit designed for the visually impaired, encourages visitors to handle mineral specimens.

For the armchair traveler, the Earth Science Discovery Lab offers field trips via an interactive video to some of the nation’s most important geological sites. On the itinerary: the volcanic ash of Mount St. Helen’s, the earthquake faults of the Bay Area, the gem mines of Maine--all are just a touch away.

Docents are also available to help visitors and student groups make the most of the lab’s scientific equipment.

“Hopefully some of the young people would come away inspired to perhaps go further into the earth sciences,” Estavillo said.

But the young aren’t the only ones being wooed. The hall, the museum’s largest permanent exhibit, “is also for the older generation that might find modern technology a little bit alien to them,” Estavillo said. “We’d like to introduce them to something like lasers or optical microscopes in such a way that they aren’t afraid to come in contact with modern technology. It’s a very user-friendly exhibit.”

The hall is actually coming together in stages. Part one, the Bruder Family Mineral Gallery, opened in 1989 and is home to constantly changing displays of gems and minerals from throughout the world. Opening today are the interactive exhibits, the Earth Science Discovery Lab and a photo gallery.

Set for a summer opening is a re-creation of a San Diego County mine tunnel, complete even to its ore car. Local gems will be showcased in a series of gem pockets; one will even display the minerals in their natural setting of mud and clay. “It will help get across the idea that minerals do come out of the ground,” said Bill Coleman, exhibits chairman, who supervised the design and construction of the hall.

And one day, if another $100,000 can be found, a chamber of lights and mirrors will give visitors the illusion that they are shrinking to the size of atoms for a journey deep within a crystal.

The idea for the hall was born four years ago, when museum officials decided to put a desert exhibit where the minerals were once displayed. That meant a new home had to be created for the museum’s impressive but fairly static exhibit of minerals and gems.

Initial plans threatened a “fairly boring” hall, Coleman said, “until somebody said why don’t we start doing the interactive exhibits.”

Museum officials liked the idea of giving the public more than the traditional rocks behind glass, and so did the National Science Foundation, which donated $200,000 for the interactive exhibits. Ideas were solicited from museums throughout the country, the plans snowballed, and the result is “even better than expected,” Coleman said.

The hall, named after a longtime museum patron and funded through a combination of grants, donations and general funds, is bigger than normal for a museum of its size because of San Diego’s large community of mineral enthusiasts and its rich mining history, Coleman said.

Estavillo said he hopes the hall will make people more aware of the treasures underfoot--treasures that each year become harder to find.

“You know,” he said, “they mine a big hole, and they don’t put anything back in it. Lots of these minerals are one-time affairs, and here’s an opportunity to see them before they disappear.”