Although called blue, the colour is a slaty or drab tone.
The bark, very dark externally, is an excellent tanning substance; the inner layers form the quercitron of commerce, used by dyers for communicating to fabrics various tints of yellow, and, with iron salts, yielding a series of brown and drab hues; the colouring property depends on a crystalline principle called quercitrin, of which it should contain about 8%.
The skins that are not perfectly white are dyed jet black, dark or light smoke, violet-blue, blue-grey, and also in imitation of the drab shades of the natural blue.
In the XIIth Dynasty a hard thin drab ware was common, like the modern qulleh water flasks.
Has a close dark drab underwool with yellowish grizzly, grey, regular and coarse top hair.
In the latter part of the XVIIIth and the XIXth Dynasties a thick hard light pottery, with white specks and a polished drab-white facing, was generally used for all fine purposes.
The female is drab, but shows the same white markings as the male, and the young males resemble the females until after the first autumn moult, when they gradually assume the plumage of their sex.
Is widely distributed throughout the state, and great quantities of it aie crushed for road-making, railway ballasts, and concrete, but as the prevailing colours are greyish or drab it is little used in the walls of buildings.
Subsequently the hard top hairs are taken out as in the case of otters and beavers and the whole thoroughly cleaned in the revolving drums. The close underwool, which is of a slightly wavy nature and mostly of a pale drab colour, is then dyed by repeated applications of a rich dark brown colour, one coat after another, each being allowed to thoroughly dry before the next is put on, till the effect is almost a lustrous black on the top. The whole is again put through the cleaning process and evenly reduced in thickness by revolving emery wheels, and eventually finished off in the palest buff colour.