Methods of Conserving Archaeological Material from Underwater Sites
by Donny L. Hamilton

Gold and Gold Alloy Conservation

Gold is a relatively inert metal and thus undergoes minimum corrosion. It is the copper- and/or silver-based gold alloys that easily corrode, resulting in silver or copper corrosion compounds that leave an enriched and possibly weakened gold surface.

Pure gold and high gold alloys do not require any conservation treatment. Gold objects from shipwreck sites appear to look the same when recovered as the day they went down with the ship. The copper and silver in low- alloy gold do corrode. When present, the copper and/or silver corrosion compounds of low-alloy gold are treated by the processes described for these two metals (see Files 12 and 13). Silver corrosion products can be removed with ammonia; copper compounds with formic acid, citric acid, or alkaline sequestering agents, such as Rochelle salts or alkaline glycerol. All the pertinent comments applicable to silver and copper conservation are made under those headings.

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