Gold and Salt Water
Country: United Kingdom
Date: Summer 2009
I would like to know if gold would decompose in salt water and
what the state of a gold necklace submerged in salt water be like after 20
years. Would the gold necklace be intact or would decomposition of the metal
have occurred? If so, what would be the state of it?
Assuming you are talking about pure gold (not low-carat), the gold
itself is not going to substantially degrade. Gold does not readily
oxidize, which is one of the reasons it has been used as money. In the
ocean, many things might stick to it though, and cause it to be
covered. Because gold is so soft, it is not easy to clean (without
damage) once things like barnacles are stuck to it.
Hope this helps,
Gold will not "decompose" in salt water. In fact, salt (or sea) water
will not affect gold in any way, no matter how long the gold is
exposed to it. Not only is gold unaffected by salt water, it is also
totally unaffected by most strong acids. The only thing that will
attack gold at normal temperatures is "Aqua Regia", which is mixture
of 1 part concentrated nitric acid, to 3 parts concentrated
hydrochloric acid. Gold will slowly dissolve in this mixture, but is
unaffected by just pure nitric acid or pure hydrochloric acid (or any
other common acid).
So to answer your specific question, your gold necklace after 20 years
exposure to salt water would look like new. This assumes pure gold,
and not an alloy.
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Update: June 2012