Though the park's open year-round, it's best to visit in the spring, when the seasonal rains make it easier to locate the biggest diamonds. We wanted to visit in April, but, as is typical to offbeat travelers, we came when we could. So, we bought our five-dollar day passes, gathered our strainers, spades, and rented gear, and headed off to the fields. We were aiming for diamonds, of course, but they're not the only precious stones hidden in the soil. There's well-rounded jasper, multi-colored agate, angular quartz and amethyst, milky white calcite, and shiny flecks of mica, or "fool's gold".

Looking for Gems
Regardless of what you're looking for, there are three basic ways to search.

The easiest way is to observe the surface or turn the topsoil over with gardening tools, looking for crystals that have been exposed by rain or plowing. An old diamond hunter, fond of this method, frequently sits on the edge of the fields in a folding chair, drinking a gin and tonic (Sprite to the park officials), waiting for the sunlight to show him the way. When he spies something glinting in the distance, he walks straight out towards it, often discovering a diamond in the topsoil.

The other two ways are slightly more challenging, involving a process known as screening. When the soil's dry, you can shake fistfuls of dirt over a box screen or strainer to find minerals that are too large to fit through the mesh.

But, the most effective method is probably the most time-consuming. Using water available in large bins on the mine, you can shake and wash the dirt through two screens - a top one that filters everything but larger rocks and a bottom one, with tinier mesh, that catches smaller gems.

Doing it
Barely anyone was there when we trekked across the fields, towards one of two sheltered screening areas, and began our dig. Dan filled a bucket with dirt from a nearby field. Scooping a few handfuls onto our screens, we shook the box frames in the water bin and patiently sifted through the dirt, sometimes having to squish chunks of clay against the mesh to loosen them up. When nothing but rocks and potential gems were left in our screens, we turned them over on a nearby workbench and let the piles of gravel dry a bit before sifting through them more carefully.

You'd be surprised how many rocks and minerals can be found in two handfuls of ordinary-looking dirt. Although diamonds are rare, quartz pieces and colorful rocks are almost always a guarantee. But don't give up on the diamonds - plenty have been found over the years. At the Crater, they're typically well-rounded white, yellow, or brown stones, about the size of a match head, with a metallic shine and an oily, slick surface to which dirt won't stick. Any crystal that doesn't get scratched or crushed under the pressure of a fingernail or pocketknife may, in fact, be a diamond. Just to be sure, the staff will weigh and certify your find free of charge.

It's possible to find one, but it's no easy feat. You could spend the whole day sifting through dirt and even cart home a 5-gallon bucket of washed gravel, only to find a handful of quartz, as we did. But, for five bucks to get in and a little bit more to rent the necessary gear, it's a lot of fun, and, better still, whatever you find, you keep. And there's always the chance you might find a record-breaking jewel, like the 40-carat Uncle Sam excavated at the Crater in 1924, one of the largest diamonds found in America.

Can Cartier's guarantee such a find for so low a price tag? We think not, which is why we'll be back there again next spring.