Hardness - Physics of Nondestructive Evaluation - material hardness
…infusion of new stocks of precious metal, especially silver, into the money supply. The medieval economy had suffered from a chronic shortage of precious metals. From the late 15th century, however, silver output, especially from German mines, increased and remained high through the 1530s. New techniques of sinking and draining…
Many Asian countries have produced gold from alluvial stream deposits in past centuries, and some have continued to do so. Small volumes of alluvial gold are produced in Myanmar, Cambodia, and Indonesia, and the headwaters of the Yangtze River in the Tibetan border…
Bronze, iron, and brass were, then, the metallic materials on which successive peoples built their civilizations and of which they made their implements for both war and peace. In addition, by 500 bce, rich lead-bearing silver mines had opened in Greece. Reaching depths…
Of gold’s properties, when it was first discovered (probably in Mesopotamia before 3000 bce), it was the metal’s malleability that was a new phenomenon: only beeswax, when heated to a certain temperature, could be compared to it. Gold’s molecules move…
…are the source of various precious metals, most notably gold, silver, and platinum. They also are the ore minerals of most metals used by industry, as for example antimony, bismuth, copper, lead, nickel, and zinc. Other industrially important metals such as cadmium and selenium occur in trace amounts in numerous…
…currency in any form of precious metal. Consequently the volume of currency is determined by the actions of the government or central bank and not by the supply of precious metals.