Bole

Bole is an earthy mineral resembling clay in structure, and consisting essentially of silica, alumina, red oxide of iron, and water, which occurs in nests and veins in basalt and other trap rocks. It feels more or less greasy when placed between the fingers; is of different colours—yellow, red, brown, and black; has a dull, resinous lustre, but a shining streak; and is readily friable and not plastic. Armenian bole has a red tint, and is used for colouring tooth-powders and false anchorvies. Lemnian Earth (containing a large percentage of silica) is the bole from the island of Lemnos; it is red in colour, and was at one time prescribed as a tonic and astringent medicine—no doubt from the large percentage of oxide of iron present. The boles which are employed in veterinary practice in Europe are generally made from Armenian bole. The savage tribes in South America eat bole to allay the pangs of hunger. When bole is calcined, it becomes hard; and when afterwards levigated, a coarse red kind is used as a pigment. French bole is pale red; Bohemian bole, reddish yellow; Silesian bole, pale yellow; and Blois bole is yellow.