Whetstone, is a kind of sand-stone, dug up chiefly in Derbyshire, and other northern counties. It is of a dusky-yellow colour ; resists the action of acids, though permeable to water : being of a rough, and coarse structure, it is easily crumbled or broken between the fingers, and will not strike fire against steel. This fossil affords an useful article of trade, and is employed for sharpening knives, scythes, biils, and other implements of rural and domestic economy.