This cache is part
of the Vermont Periodic Table
(VPT) series of
caches.
About
the Element:
Brief Description:
most metals are metallic grey or silvery white whereas gold is
characteristically a metallic yellow colour, in other words
gold-coloured. Caesium is also gold coloured. The gold colour seems
related to relativistic effects of the outermost gold orbitals.
Small amounts of other metals alloyed with gold change the
colour as well as mechanical properties such as hardness. White
gold for jewellery is formed by mixing palladium, silver, or nickel
with gold, although the result is green gold with certain
proportions of silver. White gold is commonly used for wedding
rings in the USA. Addition of some copper gives "rose gold", a soft
pink colour. Remarkably other colours such as purple (a
gold:aluminium alloy), blue (a gold:indium alloy) and even black (a
gold:cobalt alloy) may be formed.
Gold is usually alloyed in jewellery to give it more strength,
and the term carat describes the amount of gold present (24 carats
is pure gold). It is estimated that all the gold in the world, so
far refined, could be placed in a single cube 60 ft. on a side. It
is metallic, with a yellow colour when in a mass, but when finely
divided it may be black, ruby, or purple.
It is the most malleable and ductile metal; 1 ounce (28 g) of
gold can be beaten out to 300 square feet. It is a soft metal and
is usually alloyed to give it more strength. It is a good conductor
of heat and electricity, and is unaffected by air and most
reagents.
Gold is readily available commercially and its price (see the
UtiliseGold directory)
changes day by day and is one of the most widely tracked commercial
prices.
The most common gold compounds are auric chloride
(AuCl3) and chlorauric acid (HAuCl4). A
mixture of one part nitric acid with three of hydrochloric acid is
called aqua regia (because it dissolved gold, the King of Metals).
It is unaffected by air and most reagents. It is found free in
nature and associated with quartz, pyrite and other minerals. Two
thirds of the world's supply comes from South Africa, and
2/3 of USA production is from South Dakota
and Nevada. Gold is found in sea water, but no effective economic
process has been designed (yet) to extract it from this source.