The four tests
Work through these in order. Anything that passes all four is gold.
1. The shade test: move into shadow
Gold looks the same in shadow as in sunlight: a soft, buttery, unchanging yellow. It does not sparkle and it does not go dull.
Pyrite (fool’s gold) and mica are reflective, not self-coloured. Move them into shadow and they go grey, dark or black. Tilt them in the light and they flash on and off. Gold just sits there, glowing.
This one test eliminates the overwhelming majority of false positives.
2. The malleability test: press it
Gold is soft and malleable. Press a flake against something hard with a pin or a knife point and it will bend, flatten and smear. It will not break.
Pyrite is brittle: it crumbles into angular black-grey powder. Mica is elastic and flakes apart into thin sheets. Neither smears.
3. The streak and shape test: look at the edges
Under a 10× lens, gold grains are rounded, smoothed, irregular and often folded, with a lumpy, waxy surface. They look like something that has been battered.
Pyrite is crystalline, it forms cubes and pyritohedra with straight edges and flat faces. If you see a perfect little cube, it is pyrite. Mica forms thin, flat, hexagonal plates you can see through at the edges.
4. The float test: tap the water
Fine mica floats, or hangs suspended in the water, and skates away from your finger. Gold sinks instantly and stays put no matter how hard you swirl. When you tilt the pan, gold sits firmly at the back of the black-sand tail; mica washes forward with the light material.
The Devon look-alike gallery
| Mineral | What gives it away | How common here |
|---|---|---|
| Muscovite / biotite mica | Flat flakes, flashes on and off, floats, breaks into sheets | Very, the commonest false positive on Dartmoor |
| Pyrite | Crystalline cubes, brittle, black streak, dulls in shadow | Common in the Devonian slates |
| Chalcopyrite | Brassier and more iridescent, often tarnished blue-purple | Common near copper workings |
| Cassiterite | Dense, dark resinous brown, not yellow, non-magnetic, very heavy | Common, this is Dartmoor tin ore |
| Brass and lead shot | Perfectly regular shapes, machining marks | Common near roads, farmyards, shooting ground |
| Weathered slag | Glassy, bubbled, unnaturally coloured | Near any historic mining or smelting site |
What south Devon gold actually looks like
This is the part generic panning guides cannot tell you, and it is worth internalising before you go, because Devon gold does not look like the photographs.
Small. Fine grains and flakes, typically well under a millimetre. There are no nuggets in the modern record.
Dendritic. This is the striking one. Many South Hams grains are branching, fern-like or otherwise “very intricate in shape with projections” Leake 1992. If you find something that looks like a tiny gold twig or snowflake, you have found something genuinely characteristic of this region, and it means you are close to its source, because those projections cannot survive transport.
Sometimes pale or oddly coloured. The gold here carries palladium, with some rims up to 13% Pd, and grains of potarite (PdHg) occur alongside it Leake 1990. Palladium-rich gold reads paler and whiter than pure gold. A grain that looks like slightly-off silver rather than gold may be more interesting than an obviously golden one, not less.
Silver-rich rims. East of the Erme in particular, many grains have relatively silver-rich rims over a silver-poor core Leake 1988. Under a lens this can show as a subtle colour zoning across the grain.
Not detectable. Fine flaky gold does not register on a metal detector. Detecting is also prohibited on Dartmoor access land without the Authority’s authorisation Dartmoor National Park Authority. The pan is the instrument here.
Recording what you find
If you are doing this seriously, treat every find as data:
- Photograph it wet, in the pan, before you lift it. With something for scale.
- Note the position: a six-figure grid reference or a phone GPS pin.
- Note the context: bedrock crevice, gravel bar, depth, what the surrounding stone was.
- Bag concentrate separately per site. One vial per sampling point, labelled.
- Keep a tally of barren sites too. Where you found nothing is half the map, and it is the half everybody throws away.
If you think you have found something significant
Genuinely unusual finds are worth reporting rather than pocketing. The BGS record mineral occurrences, and a well-documented find with a location and a photograph is a real contribution: the entire south Devon Au-Pd story began with someone noticing that gold grains in a routine drainage sample looked wrong Leake 1991–2004.