A stone differs from an earth in consistence only; but there are some bodies, evidently stony, which contain no earth, as the diamond. The mineralogists who arranged fossils from their external forms, of course distinguished stony bodies, but this arrangement has been superseded by the chemical systems of the moderns; and Wallerius is the last author of credit who has followed it. Stones are defined by that naturalist as hard bodies which cannot be cut with a knife, seldom rasped by a file, brittle, without ductility, insoluble in water or oil; but falling into small particles by exposure to air.
We need not pursue the qualities of stones farther than to mention Wallerius' subdivisions of this class of bodies into calcareous,- vitrescible, fusible, and those unaffected by fire. The compound stones he styles rocks.
It will be obvious from the medical bodies styled
"stones," which follow, with what little accuracy the
5 R 2 term has been bestowed. It is, however, now disused in a very great degree, and will not be again revived. Wallerii Systema Mineralogicum. See Mineralogy.
Lapis Calaminaris. See Zincum.
Lapis calcareus. Lee Calx.
Lapis ampelites. Canal coal. See Ampelites.
Lapis benzahan. See Bezoar fossile.
Lapis bezoar, and Peruvianus. See Bezoar orientalis and Occidentalis.
Lapis porcinus et malacensis. See Bezoar hys-tricis.
Lapis septicus. Melted kali.
Lapis nephriticus is a variety of the jaspis, theyade of Hauy iv. 368; of the Sciagraphia; and of Kirwan, vol. i. p. 171. It is very hard, but melts in the focus of a mirror, to a transparent glass, with some air bubbles. Its specific gravity is about 3. Its look and touch greasy, and it contains about 0.38 of magnesia. It is celebrated for relieving the pains of gravel, and even of destroying the calculus. It has this effect, it is ridiculously supposed, when hung about the neck. Boot Gemmarum et Lapidum Historia, ii. 110.