I've been collecting rocks in the California desert since 1974, when a fellow I worked with took me out past Barstow one November weekend and handed me a rock hammer and told me to look for anything that didn't look like the rocks around it. I came home with forty pounds of stuff, most of it worthless, and I've been going back ever since. My wife says the garage is a geologic hazard. She's right.

This page is for people who want to get started. I'm not going to give you exact spots, and if you write and ask I'll tell you the same thing: any place I name here is a general area, big enough that you'll have to do your own looking. That's not me being stingy. It's how you learn, and it's how the good spots stay good. There's a lot of desert. Go find some.

The most important thing on this page: it's over a hundred degrees out there from May through September. I don't go, and I've been doing this twenty-five years. Season is October to April. Wait for it.

People get nervous about this and they don't need to, as long as they pay attention. Here's the general picture. It's the way I understand it; the BLM office is the final word, and the rules can change, so ask them if you're not sure.

Where you CAN collect:

• Most BLM land (that's the Bureau of Land Management, the federal agency that manages a huge part of the desert). You're allowed to pick up small amounts of rocks, minerals and common invertebrate fossils (shells and the like) for your own personal, non-commercial use, without a permit. "Small amounts" means what a hobbyist carries out, not a truckload. You are not supposed to sell it. Hand tools only. No digging that leaves a mess; fill in your holes.
• Petrified wood on BLM land has its own rule: up to 25 pounds a day plus one piece, and no more than 250 pounds a year. I've never come close.
• Private land, with permission. Ask. People are usually decent about it if you ask first and show them what you found after.

Where you CAN'T collect:

• National parks and national monuments. No collecting of anything, period. In our part of the world that's Death Valley and Joshua Tree, which became national parks in 1994, and the Mojave National Preserve, which was created the same year and is run by the Park Service. A lot of country that used to be open got closed that year. If you learned your spots before 1994, check them again.
• State parks. Same.
• Military land. There's a lot of it out here and it's fenced and signed and they mean it. Fort Irwin, China Lake, the Marine base at Twentynine Palms. Don't.
• Mining claims. Somebody who's filed a claim owns the minerals on it. You'll see claim markers: a post, a pile of rocks with a can or a plastic pipe stuck in it, sometimes a sign. If you see them, stay off unless the claim holder says otherwise. There are old, dead claims all over the desert too, but you can't tell by looking, so treat them all as live.
• Wilderness areas. The 1994 desert law made a lot of new wilderness. No vehicles off the road, no motorized anything. Whether you can pick up a rock inside one is a question for the field office; I stay outside them to keep it simple.

Things you never collect anywhere: Indian artifacts of any kind, arrowheads included. That's federal law, and it's also just right. Vertebrate fossils (bones, teeth) on public land; leave them and report them. Anything from a historic site, an old mine building, a cabin. Take a picture.

And the rule that isn't a law: leave the place better than you found it. Pack out your trash and somebody else's. Don't drive off the road. Don't leave holes. There's a reason a lot of the old spots got closed, and some of it was people like us.

What you don't need: anything with a battery that you're counting on. Metal detectors are for a different hobby. A cellular phone is nice if you have one but out where the rocks are it probably won't get a signal, so don't plan on it.

Beginners ask this more than anything, and the answer is simpler than the books make it.

Agate and jasper are the same mineral. Both are chalcedony, which is quartz in crystals too small to see. Both are hard (7 on the Mohs scale, meaning they'll scratch glass and a steel knife blade won't scratch them). Both take a beautiful polish. The difference is just this:

• Agate is translucent. Hold a chip up to the sun, or put a flashlight behind it, and light comes through, at least at the edges. Agate is often banded, in layers, sometimes with a hollow center lined with crystals.
• Jasper is opaque. No light comes through, even at a thin edge. Jasper is usually a solid color or a pattern of colors: red, brown, yellow, green, and every combination. The reds and browns come from iron.

That's it. Same stuff, one lets light through and one doesn't. You'll find pieces that are half and half, and rockhounds argue about those in the parking lot, and it doesn't matter.

How to spot either one in the field: Look for rocks with a waxy or glassy look where they're broken, instead of grainy or dull. Look for rocks that are smoother and more rounded than their neighbors, because chalcedony is harder and wears slower. Wet it with the spray bottle; the color jumps out. The easiest way to learn is to bring home a bunch of rocks, wet them all, and look at which ones you'd want on a shelf. Those are the ones.

Geodes: A geode is a rock with a hollow inside, usually lined with crystals, usually quartz. From the outside it's a lumpy, roundish rock, often with a bumpy surface like a cauliflower. Two tricks: a geode is lighter than a solid rock the same size, because it's hollow, so heft everything round; and if you shake one you can sometimes hear loose crystals rattle. Don't crack them in the field. Take them home and open them with a chisel around the middle, or if you get serious, the plumbers' chain pipe cutter that rockhounds use; it pops them clean in two. A rock that looks like a geode and turns out solid is a thunder egg or just a nodule, and some of those are the prettiest things in my garage.

Like I said: areas, not spots. Get a map and go look.

A rock tumbler is a rubber barrel on a motor that turns for weeks. The rocks ride around in grit and water and wear each other smooth, the same thing a river does, only faster. A small rotary tumbler runs sixty or seventy dollars at a rock shop and lasts forever if you keep the barrel clean. Agate and jasper tumble beautifully because they're hard and take a polish. Here's how I do it. It takes about a month a batch, and there's no hurrying it.

1. Sort by hardness. Only tumble rocks of the same hardness together. Agate and jasper together, fine. Throw in a softer rock and it'll be ground to nothing and gum up the batch. Mix sizes, though: some big, some small, some pea-size. The little ones get in between.
2. Load the barrel two-thirds to three-quarters full of rock. Less than that and they bang instead of rub, and you'll get chips. If you're short of rock, add plastic pellets from the rock shop to fill it out.
3. Stage 1, coarse grit. Silicon carbide, 60/90 grit, about two tablespoons per pound of rock. Add water to just below the top of the rocks. Seal it, run it seven days. Open it and check: rocks should be rounded off, no sharp edges. If they still have edges, rinse and run another week with fresh grit. Anything that's cracked, take out now; a crack traps grit and ruins the polish.
4. Rinse everything. This is where most people mess up. Every speck of coarse grit has to be gone from the rocks, the barrel, and the lid before the next stage, or one grain of it will scratch the whole batch. Scrub with an old toothbrush. Do not pour the slurry down the drain. It sets up like cement in your pipes. Pour it on the driveway or in a hole in the yard.
5. Stage 2, medium grit. 120/220 silicon carbide, same amount, seven days. Rinse just as carefully.
6. Stage 3, fine grit (pre-polish). 500 grit, seven days. The rocks will start to look smooth and a little shiny when wet. Rinse.
7. Stage 4, polish. Aluminum oxide or cerium oxide polish, a tablespoon or so per pound, plus the plastic pellets to cushion. Seven days. When you open it, the rocks should shine dry. If they're cloudy, they weren't ready for polish; go back a stage.
8. Burnish (optional but I do it): a day in the barrel with a little grated bar soap and water, no grit. Takes off any haze.

Keep a log on the garage wall: what went in, what day, what stage. Four weeks is a long time to remember whether it was Tuesday or Thursday. And keep the tumbler somewhere you can't hear it, because it sounds like a dryer full of gravel, which is what it is.

When they come out, the good ones go in a dish by the front door for visitors to pick from. The rest go on the shelf. The shelf is full. I'm building another one.

Frank Delacroix. Retired from the water district after twenty-nine years, which is where I learned to read a topographic map. Member of a gem and mineral club that meets once a month in a church hall and has a show every spring. Married thirty-three years to a patient woman. One garage, full.

I put this page up because the young fellows at the club kept asking the same questions, and because a lot of what's out there about the desert is either people who want to sell you something or people who want to tell you exactly where to dig, and I don't hold with either. Write if you've got a question. I'll answer it if I can. I won't give you my spots, but I'll tell you how to find your own, which is better.

Some other pages here you might like: Desert Rats Off-Road Club (they know the roads), Camp Cook Carl (what to eat out there), and Fossil Hunting in the Midwest, which is the same hobby with more rain.