Gold is a rare metal. Therefore it only exist in – on average - very small amounts here on earth. But in some places, most commonly in the mountains, there are high concentrations of gold, so called gold-bearing ores. But to just go out to look for gold-bearing ores in the mountains without equipment is silly. The ore is usually covered with earth, stone, gravel and sand. Because of it they are not easily found.
Mountains whiter down with time. Tall, alp-like mountains eventually erode down to rounded hills, a process that take many millions of years. While the erosion is ongoing, the mountain withers down into stone, gravel and sand, which then slides down along the sides of the mountains down into the valleys in between the mountains. If there is(or once was) a gold-bearing ore in the mountain, then the withered down gravel -right below the ore - will contain some gold grains.
If one where to examine such gravel one where to find out what the mountain directly above the gravel consists of. Or what it ones consisted of.
At the bottom of the valleys flows the water, a river or a stream. The bed of the watercourse may consist of solid rock or withered down gravel (whit the rock bed underneath it of course). Flowing water has a wonderful property that prospectors like. It sorts the gravel after size and wight. At places where the ground is sloping a lot, as it usually does in the mountains, the water flows fast. A fast flowing stream "picks up" gravel and sand from its bed or from its beaches. If the watercourse passes trough an area whit gold-bearing, withered gravel both the gravel and the gold will get dragged along for a while. A stretch of rapids - with fast flowing water - picks up gravel. The longer the stretch of rapids is the more gravel is picked up. When the watercourse loses its momentum it will loose its load of (gold and) gravel. But, it does not loose it all in one place and at one time. Heavy particles such as coarse gravel and gold is dropped first, powdery sand and clay particles stay whit the water for a much longer distance.
A short stream thus picks up gravel from a small area, while a long stream picks up gravel from a wide area. Long streams - preferably at least one kilometer - is therefore of the utmost interest. Not that we should be looking for gold in a stream. At least not to start with. We should only concern ourselves whit how it looks like where the stream begins to level out. That's where we start! In the rapids, there are no major collections of gravel. But where the rapids begin to level off is where the first gravel banks will appear. This is a good place to take our first shovel of gravel and sample pan. When we pan the gravel we are investigating if that mountain in fact consists of (or consisted of) within a very large area, upstream of the test site. If one finds gold there then it comes from upstream. The gold you find in the rivers and streams, you'll find more of up in the mountains. If you want to find the origin of the gold – the gold-bearing vein up in the mountain- Then you'll just have to pan your way up the stream until you arrive at the vein. But before you do that you should probably study some books on the subject, for example the CD “guldgrävning”.