Sulfides, Arsenides and Tellurides
The sulfides are simple compounds of one or more metallic elements or semimetals with sulfur, a nonmetallic element. Typical sulfide minerals, such as galena and sphalerite, are relatively soft, heavy, and brittle, with a distinct metallic luster; a few, such as pyrite, give off a sulfurous odor when struck with a hammer. The semimetallic elements tellurium and selenium or arsenic may substitute for one or more of the sulfur atoms. The mineral thus formed, which is described as a telluride or an arsenide, shows physical properties much like those of the simple sulfides.
Most sulfides are readily altered by weathering at the Earth's surface. The water-soluble sulfide minerals may then be carried far underground with heated groundwater, later to be redeposited at greater depth. This process of secondary enrichment, also called sulfide enrichment, may result in rich deposits of copper, lead, zinc, or other metallic ores.
- Chesterman, Charles W. The Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf: New York (1987)