Short answers, pulled from the story.
Gold is a chemical element with the symbol Au, from the Latin aurum, and atomic number 79. In pure form it is a bright metallic yellow, dense, soft, malleable, and ductile transition metal, and one of the least reactive elements, ranked second lowest in the reactivity series after platinum.
Gold forms through three cosmic sources: supernova nucleosynthesis, neutron star collisions, and magnetar flares, all driven by the r-process of rapid neutron capture. The GW170817 neutron star merger observed in August 2017 generated between 3 and 13 Earth masses of gold, and in 2025 magnetar flares were confirmed as a further source.
The Witwatersrand basin holds the richest gold deposits on Earth, with roughly 22% of all known gold extracted from its rocks. Discovered in 1886, the deposit launched the Witwatersrand Gold Rush and founded Johannesburg, and the Vredefort impact 2.020 billion years ago tilted the gold-bearing rocks to reach the surface there.
Gold is slightly reddish-yellow because of relativistic quantum chemistry, which greatly reduces its 5d-6s band gap when relativity is included in calculations. A similar effect gives metallic caesium a golden hue. Light transmitted through thin gold leaf appears greenish-blue, since gold strongly reflects yellow and red.
Most gold coins ceased to circulate as currency in the 1930s, and the world gold standard was abandoned after the Nixon shock of 1971, when the United States refused to redeem its dollars in gold. Switzerland was the last country to tie its currency to gold, ending the link by a referendum in 1999.
About 10% of new gold goes to industry, chiefly as corrosion-free electrical connectors in computers and devices, with a typical cell phone containing about 50 mg of gold. In medicine, the compounds sodium aurothiomalate and auranofin treat arthritis, and the isotope gold-198, with a half-life of 2.7 days, is used in nuclear medicine and some cancer treatments.
Yes, several people attempted it, most fraudulently. Prescott Jernegan ran a gold-from-seawater swindle in the United States in the 1890s, and Fritz Haber researched extraction to help pay Germany's reparations after World War I. After analyzing 4,000 samples averaging just 0.004 parts per billion, Haber concluded extraction was not possible and ended the project.