In the deposition of gold the colour of the deposit is influenced by the presence of impurities in the solution; when copper is present, some is deposited with the gold, imparting to it a reddish colour, whilst a little silver gives it a greenish shade.
Although new-born fawns are spotted, the adults are in the main uniformly coloured; the general tint of the coat at all seasons being reddish tawny with a more or less marked tendency to grey.
Birds of either phase of plumage pair indiscriminately, and the young show by their earliest feathers whether they will prove whole or parti-coloured; but in their immature plumage the upper surface is barred with pale reddish brown.
A very thin soil covers the Edwards Plateau, but on the Llano Estacado are brownish and reddish loams derived from the sediments of a Neocene lake.
The nuts are again boiled, and the inspissated juice of the second decoction yields a weaker catechu of a brown or reddish colour.
There are two principal varieties - silver cochineal, which has a greyish-red colour, and the furrows of the body covered with a white bloom or fine down; and black cochineal, which is of a dark reddish brown, and destitute of bloom.
These last have a white or reddish ground, with ornamentation in blue, red, brown or black, and are of much better manufacture than the modern pottery of the country.
The general colour above is reddish fawn, separated from the white of the under-parts by a dark band on the flanks.
Some miles lower down, at Leitmeritz (433 ft.), the waters of the Elbe are tinted by the reddish Eger, a stream which drains the southern slopes of the Erzgebirge.
The geological formations thus exposed show that the plateaus are composed of a base of eruptive material, overlaid by enormous deposits of reddish sandstones, conglomerates and quartzites, exposed in parts to a depth of 2000 feet.