Mercury poisoning in humans causes incurable brain function damage and severe retardation.Gold extraction is also a highly energy-intensive industry, extracting ore from deep mines and grinding the large quantity of ore for further chemical extraction requires nearly 25 kWh of electricity per gram of gold produced. Monetary use
Gold has been widely used throughout the world as money, for efficient indirect exchange (versus barter), and to store wealth in hoards. For exchange purposes, mints produce standardized gold bullion coins, bars and other units of fixed weight and purity. The first known coins containing gold were struck in Lydia, Asia Minor, around 600 BC. The talent coin of gold in use during the periods of Grecian history both before and during the time of the life of Homer weighed between 8.42 and 8.75 grams. From an earlier preference in using silver, European economies re-established the minting of gold as coinage during the thirteenth and fourteenth centuries.Bills (that mature into gold coin) and gold certificates (convertible into gold coin at the issuing bank) added to the circulating stock of gold standard money in most 19th century industrial economies. In preparation for World War I the warring nations moved to fractional gold standards, inflating their currencies to finance the war effort. Post-war, the victorious countries, most notably Britain, gradually restored gold-convertibility, but international flows of gold via bills of exchange remained embargoed; international shipments were made exclusively for bilateral trades or to pay war reparations.
New World Gold: Cultural Anxiety and Monetary Disorder in Early Modern Spain (2010). External links

"Gold" . Encyclopædia Britannica. Vol. 11 (11th ed.). 1911. Chemistry in its element podcast (MP3) from the Royal Society of Chemistrys Chemistry World: Gold www.rsc.org
Gold at The Periodic Table of Videos (University of Nottingham)
Getting Gold 1898 book, www.lateralscience.co.uk
Technical Document on Extraction and Mining of Gold at the Wayback Machine (archived 7 March 2008), www.epa.gov
Gold element information - rsc.org