368 17·Gold 2500- 2000- 1500- 1000 PIOD 500 Figure 17.2.World production of gold in metric tons.Source: US Geological Survey,Miner- T als and Materials Analysis 19001020*30'4050'607080902000 Section. Year price,does not drastically drop,or as long as the world supply of gold does not suddenly and excessively increase due to hith- erto unforeseen circumstances.Some economists suggest,there- fore,that the gross national product of a country would be bet- ter suited for supporting a currency.In the late 1800s,many western countries adopted the gold standard,which pledges to exchange paper money for gold at a fixed price.(The United States went on and off the gold standard and finally abandoned it in 1971.)The world's gold production and reserves are given in Table 17.1. Early chemistry and other sciences have greatly benefited from the quest of alchemists to produce gold from less precious ele- ments.Many useful substances have been "accidentally"discov- ered through their experimentations,such as the red stoneware that was invented in 1707 by an alchemist named Johann Friedrich Bottger(who,incidentally,also reinvented,in 1707/08, white porcelain and thus laid the ground for the MeiBen porce- lain manufacture in Germany;see Section 15.2.). Gold is a reasonably good conductor for electricity and heat; it is quite dense and is the most ductile,i.e.,malleable,of all met- als.Indeed,gold can be hammered into thin sheets,only 50 nm in thickness,called gold leaves.Specifically,one gram of gold can be spread out to cover about one square meter.The high es-price, does not drastically drop, or as long as the world supply of gold does not suddenly and excessively increase due to hith￾erto unforeseen circumstances. Some economists suggest, there￾fore, that the gross national product of a country would be bet￾ter suited for supporting a currency. In the late 1800s, many western countries adopted the gold standard, which pledges to exchange paper money for gold at a fixed price. (The United States went on and off the gold standard and finally abandoned it in 1971.) The world’s gold production and reserves are given in Table 17.1. Early chemistry and other sciences have greatly benefited from the quest of alchemists to produce gold from less precious ele￾ments. Many useful substances have been “accidentally” discov￾ered through their experimentations, such as the red stoneware that was invented in 1707 by an alchemist named Johann Friedrich Böttger (who, incidentally, also reinvented, in 1707/08, white porcelain and thus laid the ground for the Meißen porce￾lain manufacture in Germany; see Section 15.2.). Gold is a reasonably good conductor for electricity and heat; it is quite dense and is the most ductile, i.e., malleable, of all met￾als. Indeed, gold can be hammered into thin sheets, only 50 nm in thickness, called gold leaves. Specifically, one gram of gold can be spread out to cover about one square meter. The high es- 368 17 • Gold 2500 2000 1500 1000 500 1900 2000 Year Gold World Production (metric tons) ’10 ’20 ’30 ’40 ’50 ’60 ’70 ’80 ’90 0 Figure 17.2. World production of gold in metric tons. Source: US Geological Survey, Miner￾als and Materials Analysis Section