At first, any copper and other natural metals that were picked up from the ground were simply pounded into jewelry, ax heads, fishhooks and other items. Later, the metals were melted and poured into clay molds to form other products. Most rocks and sediments do not contain high enough concentrations of metals or minerals to be economically mined. Metals include gold, silver, iron, and aluminum. Some metals, such as nickel, cobalt and copper, may be found in the same ore deposit.
Most metal ores require processing to produce one or more suitably pure products.
Non-metals include sand, gravel, and rocks that are used in cement, concrete, and other construction materials for roads, bridges, and buildings. Americans depend on a wide-variety of rocks and minerals, many of which are imported. Annually, the consumption of minerals and metals in the United States is more than 18,000 pounds per person. Even if a rock is enriched in a valuable metal or mineral, it must also be recoverable to be considered an ore deposit. If it s too deep underground, too deep in the ocean, in isolated areas, in hostile countries, or otherwise inaccessible with current mining technologies, then it s really not an ore deposit.