How to Pan for Gold
Outdoors

Gold gets into rivers from source rock. Hydrothermal fluids, superheated water loaded with dissolved metals, move through fractures in the earth's crust and dump gold where conditions change, usually into quartz veins, usually alongside sulfide minerals. That is lode gold, the primary deposit. Weathering cracks those veins apart over geological time, and because gold does not oxidize, does not dissolve, does not react with much of anything, the liberated particles wash downhill intact, settle into stream gravels by weight, and become placer gold.

Geological maps are free from the USGS, from Geoscience Australia, from Natural Resources Canada. The rock associations that matter are granodiorite and quartz diorite intrusive bodies, greenschist-facies metamorphic belts, and anywhere quartz veining is widespread. A field sign that shows up before the map even comes out of the bag is rust-stained quartz rubble on the riverbank. That orange-brown color is limonite, from oxidized pyrite, and where pyrite-bearing quartz occurs the geological conditions for gold are often met.

Going further into the maps pays off in a way that most recreational panners never bother with. Gold does not distribute evenly through a rock body. It concentrates along contacts, the boundaries between different rock units, especially where an igneous intrusion meets its wall rock and there has been hydrothermal alteration. Those boundary zones are high-permeability corridors that focused fluid flow during mineralization. A river whose upstream catchment crosses an intrusion contact is a better prospect than one that drains the middle of a single rock unit. If a fault also cuts through that contact, creating a structural junction, the probability goes up again. This is simplified exploration targeting, the same logic mining companies use to site drill holes, applied with public data and no budget.

The Mother Lode in California follows a contact between Paleozoic metamorphics and Mesozoic intrusions. Bendigo in Australia occurs in saddle-reef quartz in Ordovician turbidites. Klondike drains sheared schists. Different continents, similar structural recipes.

Gold is 19.3 grams per cubic centimeter. River sand is about 2.65. That density ratio drives every aspect of how gold behaves in moving water. It sinks faster than anything else in the mix and ends up wherever the current loses the most energy.

The inside of a river bend is the textbook answer and it is correct, with a refinement. The highest-grade material on a point bar tends to sit not at the bend apex but slightly downstream, at the transition where the channel starts straightening. The turbulence structure reorganizes at that transition and dumping efficiency peaks there.

The orientation of the crevice relative to current direction controls this completely. Perpendicular cracks catch gold. Parallel cracks do not, because the particle just keeps sliding along the groove. When standing on exposed bedrock, scanning for the high-angle crevice sets and ignoring the parallel ones is the first decision to make.

Bedrock lithology feeds into this. Granite and gneiss weather into wide, rough-walled fracture networks that grab and hold heavy particles. Slate and basalt have tighter, smoother fractures. Where bedrock type changes along a river, the crevice productivity can shift noticeably. Some people who have panned the same rivers for years plan their whole day around where the granite starts.

Large boulders create a dead zone on the downstream side where velocity collapses. Gold drops into the first thirty centimeters directly behind and adjacent to the rock face. The temptation is to dig a big area behind a boulder. The gold is in a much smaller zone than that.

Plunge pools below falls and rapids are settling basins. Energy dissipates when the water hits the pool and heavy minerals drop to the deepest point. Often hard to access.

Paleochannels, old riverbeds now elevated above the modern stream, can be spectacularly rich because nothing has reworked them since they were active. Flat terraces on valley walls with rounded cobbles that do not match the modern river lithology are the signature. California's Tertiary channels, called blue lead for the blue-gray color of their oxygen-starved deep gravels, were phenomenally productive in the 1800s.

In high-latitude panning territory like Alaska, Yukon, and Scandinavia, seasonal freeze-thaw does something counterintuitive to gold distribution. Water in the sediment expands when it freezes, pushing grains upward. When the ground thaws, fine material drops back down faster than coarse material and fills the space underneath. Heavy particles, including gold, cannot fully return to their previous depth. Over many freeze-thaw cycles, gold migrates upward. This does not invalidate the bedrock-contact pay layer concept, but it means that in permafrost-affected drainages the gold can be distributed vertically through the column rather than concentrated strictly at the bottom. Sampling at multiple depths costs almost no extra time and reveals whether this is happening at a given site.

Any river that saw mining activity in the 19th century or earlier probably has mercury in its sediment. The old extraction method was amalgamation: pour liquid mercury into the sluice, let it bond with fine gold to form amalgam, recover the amalgam, burn off the mercury to get the gold. For every ounce of gold produced, something like an ounce to an ounce and a half of mercury went into the river and stayed there. The Sierra Nevada system in California absorbed thousands of tons of the stuff. It has not gone anywhere.

Mercury density is 13.5, so it concentrates alongside gold in the heavy fraction at the bottom of the pan. Small bright silver spheres that roll freely without sticking to anything are mercury beads. Duller gray metallic chips are amalgam fragments, mercury-gold alloy residue.

The uncomfortable part is that the rivers with the most mercury are the same rivers that historically produced the most gold and therefore attract the most recreational panners today. It rarely comes up in how-to content.

Getting gold into the pan requires digging the right material. The surface of a gravel bar is mostly recently deposited light sediment. Gold, being seven times heavier than that sediment, has long since migrated down through it. The pay layer, the material worth processing, is the ten to fifteen centimeters sitting directly on bedrock or on a dense clay horizon called false bedrock. Anything above that layer has very little gold in it.

Dig to the contact surface. Scrape the bottom material into a bucket. Clean out every crevice in the bedrock. Ignore the top.

Before committing to any one spot, test first. Grab a couple handfuls of bottom material from three or four different locations, pan each separately, and see which spot shows gold. Fifteen minutes of sampling dictates where the rest of the day goes.

The minerals that show up alongside gold in the pan carry information. Black sand, mostly magnetite and hematite, increases in concentration toward zones of better gold grades. Red-toned translucent grains are almandine garnets, indicating effective density sorting. Lead-gray dense particles may be galena or bismuthinite, sulfide minerals that co-occur with gold in certain systems.

Mica is shiny and gold-colored and fools beginners exactly once. It is flat, light, and floats at the top of the pan. It will never end up in the heavy concentrate at the bottom.

The pan separates by density. Shake to break inter-particle friction and let heavy grains sink. Tilt to let water wash off the light stuff. Repeat until only the heavy fraction remains.

Steel pans need to be heated over a fire first to burn off manufacturing oil. Oil makes the surface hydrophobic, and surface tension will float fine gold particles right out of the pan on air bubbles. Polypropylene pans, the green and blue ones with molded riffle rings, are hydrophilic out of the box.

Fourteen inches diameter works for most people. Bigger pans hold more material per load, which sounds like an advantage until the pan is full of wet sand and weighs north of seven kilos and the arms start failing after forty minutes. Technique degrades when muscles tire. Recovery rate drops with it.

Pan color is functional. Green and blue create high visual contrast with yellow gold. Even a quarter-millimeter speck pops against green. Black backgrounds hide the black sand and spotlight the gold. White or light gray makes fine gold invisible. People using pale containers lose gold they never see.

Load the pan two-thirds full, submerge it, and break apart every lump of clay by hand. This is the step where the most gold gets lost and where the least attention gets paid. Clay wraps around fine gold particles. A gold grain encased in clay behaves like a clay grain during sorting and washes out with the waste. Every clay chunk has to be crushed and dispersed. When pulling large rocks out of the pan, rinse them in the water before tossing them. Rough rock surfaces trap fine gold in their pits.

Shake the submerged pan horizontally, short even strokes, two or three centimeters, twenty or thirty seconds. This is not about force. The motion breaks static friction between grains and lets the heaviest particles work their way down through the lighter ones.

Tilt the front of the pan down, maybe fifteen to twenty degrees, and let water slide over the top, carrying away the lightest surface layer. Level the pan, shake again, tilt and wash again. Many cycles, each one removing a thin layer. The urge to tilt steep and get through it faster is where gold gets lost. Steep angle means fast water means gold gone.

When only a couple tablespoons of black sand and residual material remain, add a little water and rotate the pan very slowly. Gold separates from the black sand visually at this point because it is so much denser, settling to the absolute lowest point of the thin vortex and showing up as bright yellow against dark.

When a spot is producing and throughput matters, the sluice box is the standard step up. A trough with riffles and matting on the bottom, running water continuously through it. Feed material in the top, heavy minerals get caught in the riffles and mat, light waste washes out the bottom.

Flow rate is the critical variable. One to two centimeters of water depth at the inlet, slight turbulence on the surface, no violent whitewater. Too little flow clogs the riffles. Too much flow blows fine gold straight through. Miners Moss under an expanded metal grate is the current best matting setup.

Spiral gold wheels run off batteries or a hand crank and work with recirculated bucket water, no stream needed. Dry washers use forced air and vibration instead of water and are the only option in desert country with no surface water. Arizona and Nevada panners depend on them.

In a lot of placer deposits, gold finer than half a millimeter, the stuff that is hard to see and easy to lose, makes up half or more of the total by weight.

The blue bowl handles fine gold recovery from black sand concentrate. Water injected at the base of a conical vessel creates an upward vortex. Gold drops to the center collection groove. Black sand goes over the rim.

For home processing of black sand, a neodymium magnet with a plastic bag slipped over it pulls out the magnetite. Invert the bag over a discard container and the magnetite drops off cleanly. Trying to scrape black powder off a bare rare earth magnet is a miserable experience.

Natural placer gold sells for more than melt price. Usually one and a half to three times spot, sometimes much more for nuggets with crystal faces or interesting growth patterns. Even ordinary flakes and pickers fetch above melt if they have not been squished or deformed by handling. Use tweezers. Store by size and shape. Do not ball it all together and do not melt it down unless it is too fine or fragmented to have any specimen interest.

Floods rework everything. They tear up old deposits, throw heavy minerals into suspension, and then as the water drops, all of that material re-sorts itself under rapidly declining energy. The sorting efficiency during flood recession is high because the energy gradient is steep and continuous. Gold stacks up at every energy minimum in the channel, at point bar tails, in freshly scoured crevices, behind newly deposited boulders.

By midsummer in a dry year, the easy gold has been picked up by whoever got there first, and low-energy daily flow has spread and diluted what remained. Post-flood low water also happens to be when the most bedrock is exposed and wading is least dangerous.

Floods rearrange the physical channel too. Boulders move. Sand bars form and disappear. Bedrock surfaces that were buried get uncovered. A familiar stretch of river can have a completely different gold distribution after a major flood event.

Gold deforms when pressed with a needle. Pyrite shatters into powder. Gold glows warm yellow in shadow and in sunlight equally. Mica flashes only at certain angles and goes dark when turned. Gold ignores a magnet. Three tests, and the confusion with fool's gold or mica is over permanently.

Color varies. High-purity gold is deep yellow-orange. Gold with elevated silver content, the natural alloy called electrum, runs pale yellow to nearly white. Electrum looks wrong to people expecting classic gold color. It is gold. The silver proportion shifts the appearance. Electrum specimens actually have their own collector following because they are less common.

The shape of a placer gold particle encodes transport distance. Flat, perfectly rounded, paper-thin flakes have been tumbled a long way from the source. Thick, angular, rough-surfaced particles have not traveled far at all, maybe a few hundred meters. Finding angular gold means the lode source is close. Following the river upstream, testing at each tributary junction to see which fork still produces angular grains and which goes dead, is a prospecting method called tracing. It is tedious and sometimes goes nowhere. It is also how some major lode deposits were found historically, because somebody noticed the gold in their pan had barely been worn down and decided to follow it back.

Fine gold stored dry will disappear. Flour gold develops enough static charge to stick to skin, to fabric, to the inside of the container, to the cap. Put fine gold in a small glass vial filled with water and screw the cap tight. Larger flakes and pickers are fine in a sealed bag.

On US federal public land managed by BLM or the Forest Service, hand-tool recreational panning is generally permitted unless the specific ground is covered by an active mining claim. Claim data is searchable in BLM's LR2000 database by township, range, and section. A few minutes online before a trip reveals whether someone already holds rights to the stretch. Sluice boxes and other mechanical equipment usually require a state permit. California banned suction dredging entirely in 2009 over concerns about salmon spawning habitat. UK gold belongs to the Crown. Panning in most UK rivers requires permission from both the landowner and the Crown mineral rights holder. Australian rules are state by state; Victoria requires a Miner's Right.

Snakes. Western North American and Australian gold country is snake country. Rattlesnakes and brown snakes favor the same habitat that panners work in: rock piles, crevices, driftwood accumulations along the bank. Reach into an unseen gap in the rocks to clean out a promising crevice and the cost of that particular pan of gravel can get very high very fast. Hit the area with a tool handle first.

Fill in every hole. Stay off spawning gravel during fish reproduction windows. Leave the riparian vegetation alone. Pack out trash.