Gold is a transition metal that has a bright yellow color in its natural solid state. It is a rare and precious metal, and it is one of the most ductile and malleable of all the metals. Gold has an atomic weight of 196.966569, a melting point of 1947.52 °F, and a boiling point of 5173 °F. Gold is most commonly used for monetary and jewelry purposes. Gold is also used as a solder material, as a component in dentistry fillings and bridges, as a coloring agent in some glass, and in electronics.
Gold is found in its free native state in nature, but it is very rare. More often, gold is obtained by extraction and isolation from ore which contains gold.
The extraction process of gold is expensive and sometimes causes severe environmental damage; the isolation of gold is hardly ever produced on a small scale laboratory basis due to the expense and chemical steps involved. The beginning the extraction and isolation process of gold begins with mining ore which contains particles of gold. The ore is then subject to a variety of processes depending on what type of ore the gold is found in. Many processes crush the ore to a powder, than dissolve the rock powder in a solution of cyanide that is open to the air. A cyanide gold complex is formed, and addition of zinc powder to the complex causes pure gold to precipitate out of the solution. High purity gold is isolated using such procedures as the Wohlwill process and the Miller process. The Wohlwill process uses an electrochemical process, and the Miller process uses a chemical process to further purify gold.
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