Natural History, properly denotes small particles of siliceous stones. Sands are subject to be variously blended with different substances, as that of tales, &c. Hence, as well as from their various colours, they are subdivided into, 1. white sands, whether pure, or mixed with other arenaceous or heterogeneous particles, of all which there are several kinds; 2. the red and reddish sands, both pure and impure; 3. the yellow sands, whether pure or mixed, which are also very numerous; 4. the brown sands, distinguished in the same manner; 5. the black sands, of which there are only two varieties, a fine shining grayish-black sand, and another of a fine shining reddish-black colour; and, 6. the green kind, of which there is only one known species, namely, a coarse variegated dusky green sand, common in Virginia.

Sand is of great use in the glass manufacture; a white kind of sand being employed for making the white glass; and a coarse greenish-looking sand for the green glass. In agriculture it seems to be the office of sand to render uncultivated or clayey earths fertile, and fit to support vegetables, by making them more open and loose.

Sandstone, a compound stone, of which there are numerous varieties, arising not only from a difference of external appearance, but also from the nature and proportions of the constituent parts. See Geology and Mineralogy.