Nineteen point three
Gold’s specific gravity is about 19.3 — a cubic centimetre weighs 19.3 grams. Quartz is 2.65. Magnetite, the main black sand, is about 5.2. That gap is the whole science of placer gold. A flake of gold behaves in moving water like a pebble many times its size, so it settles where pebbles that size settle, and it needs the same current to move again. Fine flour gold is the exception: it is so thin it can ride suspended in turbulent water and travel hundreds of kilometres — which is why Alberta’s prairie rivers carry gold from the Rockies and why Edmonton panners find colour in the city.
Two consequences follow. First, coarse gold — pickers and nuggets — does not travel far from the vein or the ancient channel that shed it. If a creek gives nuggets, the source is close. Second, gold sinks through gravel over time, every flood shaking it a little deeper, until it meets something it cannot pass.
Bedrock: the floor of the trap
The richest ground in any placer is the contact between gravel and bedrock. In the Klondike, the old-timers drifted tunnels along bedrock and ignored the metres of gravel above it; in the Cariboo, the deep leads were bedrock channels buried under glacial debris. On a small scale the same rule holds: when your hole hits bedrock, slow down. Scrape the last few centimetres of gravel off with a trowel and pan it separately. Then work the cracks. Gold lodges in crevices that run across the current far better than those running with it, and it packs into the clay that fills them. A crevice tool, a stiff brush and a snuffer bottle can pull more gold out of a square metre of fractured bedrock than a shovel pulls out of a tonne of loose gravel.
Not every floor is rock. A hard, tight clay layer — false bedrock — stops gold just as well, and it is common in glaciated Canada, where till and lake clays underlie modern gravels. Treat the top of the clay exactly as you would bedrock, and don’t bother digging into it.
Where the current lets go
Gold drops out wherever the water loses speed, and rivers lose speed in predictable places:
- Inside bends. The point bar on the inside of a curve, especially its upstream head and the zone just below the apex of the bend.
- Behind obstructions. The downstream side of a boulder, a bedrock rib or a log jam creates an eddy where heavies settle. Check the upstream face too — gold piles up where the current is forced to climb.
- Below a drop. The plunge pool under a small falls or a steep riffle is a natural sluice; the gold ends up in the bottom of the pool and in the tail-out just below it, not in the falls itself.
- Where the gradient flattens. A canyon that opens into a valley dumps its load in the first few hundred metres of flat water. Bars there are worth a look.
- Old channels and benches. Rivers move. A terrace ten metres above today’s water may be the inside bend of a river that ran there ten thousand years ago. Klondike benches and the Fraser’s high bars are famous for it. Look for rounded river gravel where a river no longer runs.
Pay streaks
Put those together and you get the pay streak: a narrow ribbon of enriched gravel that follows the low-energy path down the valley, hugging the inside of each bend, crossing the channel between bends, and sitting on or just above the bedrock or clay. It rarely lines up with the middle of today’s river. Finding it means sampling in lines across the valley, not in one hole; when your counts go from two colours to twenty over a few metres, you have crossed the edge of the streak. Mark it. Work along it, not across it.
Streaks are also why a claim map matters: the productive line through a Yukon or Cariboo creek was found a century ago and is almost certainly staked. Open ground upstream or on the benches can still carry the streak’s edges.
What this means for a Saturday
Walk the stretch first. Pick the inside bends, note exposed bedrock and big boulders at the heads of bars, and check for old benches. Take test pans down to the floor of the gravel at each candidate. Count. Then commit to the best two counts and clean them to bedrock. That routine finds gold on rivers where “digging anywhere” finds black sand and a sore back — and in most of Canada it is the one method that stays legal with a pan and a hand shovel.
General information for recreational prospectors — not legal advice. Rules change and vary by site; check the official sources listed under this article and the LocalKarat “Can I pan here?” wizard before you go.
Sources
- Gold — USGS General Interest Publication
- Recreational gold panning: a visitor’s guide — Yukon.ca
- “Going for Gold in Alberta” — recreational panning guide (PDF)
- Mineral Titles Online — B.C. claim map
Updated 2026-09.