Find metal in rocks

Learn the heavy, oddly colored rocks — green-stained copper, rusty red iron, black stream sand — and where they hide.

takes patience⏳ a weektradition — not yet hand-tested

Every metal tool in the world started as a strange-looking rock. Rock with enough metal locked inside it is called ore. You cannot see the metal — the metal atoms are chemically tied to other stuff — but ore gives itself away in three ways: it is heavier than plain rock, it has odd colors, and it leaves a colored mark when scraped. This week is a treasure hunt on foot. You are not digging a mine. You are learning to see.

You need

• Your legs and a week of walking — ore hunting is nine parts looking, one part carrying.
• A hard hammerstone or hammer — to crack rocks open. Weathered surfaces lie; a fresh break shows the true color.
• A piece of unglazed fired clay — a rough pot shard works. Scraping a rock across it leaves a "streak," and the streak color names the rock better than its surface does.
• A magnet if you have any (even a scrap one) — one iron ore sticks to it.
• A bag for samples and a way to mark or remember each spot.

Steps

1. Learn the three tests before you go: heft (ore feels too heavy for its size), streak (scrape it on unglazed clay and read the color of the powder line), and fresh break (crack it open and look inside).
2. Hunt copper by its green and blue stains. Copper ore (malachite is the common one) weathers into crusts that look like green or blue paint spilled on rock.
   • Look on bare rock faces: cliff bases, stream-cut banks, hillsides where soil has washed away.
   • Even a thin green smear is worth tracing uphill — the stain washes down from the ore above.
3. Hunt iron by its rust. Iron ore is rusty red, brown, or purple-black, and heavy.
   • Hematite, the best common iron ore, can look silvery-black — but its streak is always red-brown, like dried blood.
   • Bog iron hides in marshes: crusty orange-brown lumps in the mud, near water with a rainbow sheen on it. Poke the sheen — if it breaks into stiff plates instead of swirling like oil, that is iron-eating bacteria, a good sign.
4. Read the streams. Heavy grains collect where the water slows: behind boulders, on the inside of bends.
   • Scoop that gravel into a wide pan or bowl, add water, swirl, and pour off the light sand. Black heavy sand that stays behind is often magnetite — an iron ore. Test it: it sticks to a magnet.
   • Heavy brown-black grains that do not stick may be tin ore (cassiterite). Keep them too.
5. Test everything you find: heft it against a plain rock the same size, streak it, crack it open. Keep only what passes.
6. Mark every good spot, and gather real weight — smelting needs kilograms, not pebbles. A full bag of one good ore beats ten pretty samples.

Watch out

• Fool's gold. Pyrite is brassy, shiny, often in little cubes. It fools everyone once. Its streak is greenish-black, not golden. It is an iron-and-sulfur rock — nearly useless for smelting, though it does make sparks against hard stone.
• Never lick or taste rocks. Some old-timers tasted rocks to test them. Some ores carry lead or arsenic — both are poisons that build up in you. Wash your hands after handling ore, before eating.
• Very heavy, shiny gray rock with a gray streak is likely galena — lead ore. Note where it is, but do not plan to smelt it without knowing exactly what you are doing. Lead fumes poison slowly and invisibly.
• Flying chips. Cracking rocks throws sharp splinters. Turn your face away as you strike, or shield your eyes.
• A stain is a promise, not a paycheck. One green smear does not mean a rich vein. Test small samples first; only haul loads from a spot that keeps giving.

How it works

Metal atoms in ore are bonded to oxygen, carbon, or sulfur, and those bonds are what make the strange colors and the extra weight. Copper's bonds happen to be green and blue; iron's are the colors of rust. Streams do sorting work for free: moving water carries light grains away and lets heavy metal-rich grains settle together, which is why black sand piles up behind rocks.