Prospecting for gold placer follows up the water channels in which gold and other minerals may be hidden. Basically, the gold prospector looks among these to detect samples of granitic and quartzose rocks as likely signs of gold deposits. Plenty of broken quartz is considered a good sign, but very pure, hard, dull white quartz is considered as the remaining part of the fragments of a close reef. A prospector examines closely the fine sandy matter of the stream bed, especially where eddies and backwater have been formed. A likely deposit must be scraped up, even down into every crevice and depression in the bed rock or solid rock bottom over which the river has worn its channel. This material must be panned.
Gold is often found on points and slopes of the bed rock as well as in the deepest portion. Nuggets found on high reefs above the level of the stream, imply their weight, enable them to remain in their position, during the deeper erosion of the neighboring streams and that the original vein from which came are not far off. Large nuggets and coarse gold are found much nearer to the source whence they came, than fine or flour gold, which is often carried to unlimited distances away from the plains. It has been noted that the character of quartz veins and of their enclosing rocks in the immediate vicinity decides the character too, of gravels derived from them. Hence, sometimes peculiar pebble may be traced up to the peculiar rock whence it came and the gold vein be found near that place.
It is important to mention that leads followings the course or lines of a gold bearing reef maintain a more continuous yield than those crossing a number of gold reefs at intervals. Gold is found in pockets and shoots at intervals with remaining portions. In a place where the gold quartz veins are small, though rich at wide intervals, gravels are usually small. In very deep ground where the wash is very heavy a series of boring or even shafts are made to test the quality of the bank. It is important to take samples from streams crossing the stratification planes of gold reefs at right angles. These zones usually content high gold grade. Gold is rarely found plentiful where there are indications that the current was strong, but rather in the lee under prospecting points of rock, where beaches are normally formed and the water was slack.
Essentially, gold in streams is deposited in crevices of the bed rock, which should be laid as dry as possible and picked up to such depths as the sand descends between the laminations. Terraces are shelf-like excavations and deposits upon hill slopes above valleys, and are the remains of gold glacier or river beds. The gold prospector must be find out the inlet and outlet of the terrace and examine the gravel. The wash sometimes contains gold in layers one above the other. Alluvial gold should if possible be traced to its source whence the float came. When the gold particle is large and plentiful, and the boulders large and angular, the reef is likely not far distant. Sometimes, there is a distinct peculiar feature in all the veins of a district such a peculiar band of a definite color.
It has been noted that coarse alluvial gold is not always incompatible with fine reef gold as a source due to the reef gold maybe so fine in general as to lend itself to very wide distribution when once is liberated, while the rarer coarse grains would not be transported far. Alluvial placers are richest where the current of the stream is interrupted by diminution in fall, by sudden change of direction or by entrance of a tributary, also by reefs or eddies. Absolute richness depends upon circumstances and the size and weight of floated masses. Creases, holes and fissures of bed rock over which the stream passed are favorite places for gold.