Metals

The USGS Astrogeology Research Program explains that although the USGS has been involved in impact crater research, it is neither the expert facility nor ultimate authority for confirming a feature as an impact crater. The website provides links to the...
At today's level of consumption, the average newborn infant will need a lifetime supply of 800 pounds of lead, 750 pounds of zinc, 1,500 pounds of copper, 3,593 pounds of aluminum, 32,700 pounds of iron, 26,550 pounds of clays, 28,213 pounds of salt, and...
To maintain our standard of living, each person in the United States requires over 48,000 pounds of minerals each year:12,528 lb. of stone9,385 lb. of sand and gravel888 lb. of cement280 lb. of clays418 lb. of salt309 lb. phosphate729 lb. of nonmetals589...
Granite is an igneous rock that is composed of four minerals. These minerals are quartz, feldspar, mica, and usually hornblende. Granite forms as magma cools far under the earth's surface. Because it hardens deep underground it cools very slowly. This...
Sterling silver is the standard of quality for articles containing 92.5% silver and 7.5% copper (and/or other alloys).
The fineness of jewelry gold is stated as the number of parts in twenty-four that are gold. Thus, 24 karat gold is pure gold; 12 K would be an alloy that is half gold and half copper or other metals. 
White gold was originally developed to imitate platinum, and is usually an alloy containing 25% nickel and zinc. If stamped 18 karat, it would be 75% pure gold.