horn silver, a mineral of the chloride class; chemical composition, AgCl (75.26 percent silver).
Cerargyrite contains an admixture of bromine and, more rarely, mercury. The structure is of the NaCl type but with covalent bonds between the atoms, so that the mineral is malleable and easily shaved. The crystals are rarely in a cubic system; usually there are solid wax-like masses of a gray to dark brown color. The hardness is 2.5 on the mineralogical scale; the density is 5,556 kg per cu m. Cerargyrite forms in the oxidation zone of ore deposits containing primary silver minerals, and it is a very rich silver ore.