Rotten - Stone. Rotten-stone, or tripoli, is used in the arts for polishing metallic and other surfaces. It consists entirely of the remains of animals, whose bodies were covered with an envelope of earthy matter, and whose siliceous coverings have been preserved. The following are sketches of the fossil remains of animacules, and are drawn from a microscopic view of the particles of rotten-stone. The above are specimens of the Diatomacea still more highly magnified. With the siliceous shells has been entombed, in some instances, so much of animal matter, that, in the berg, or mountain meal of Sweden, there is nutritious quality in sufficient quantity to render the mineral production edible with bread and flour.