Gold is a chemical element with the symbol Au (from the Latin
aurum, meaning shining dawn) and atomic number 79. It is a
highly sought-after precious metal which, for many centuries,
has been used as money, a store of value and in jewelry. The
metal occurs as nuggets or grains in rocks, underground veins
and in alluvial deposits. It is one of the coinage metals.
Gold is dense, soft, shiny and the most malleable and ductile
of the known metals. Pure gold has a bright yellow color traditionally
Gold forms the basis for a monetary standard used by the
International Monetary Fund (IMF) and the Bank for International
Settlements (BIS). The ISO currency code of gold bullion is
XAU. Modern industrial uses include dentistry and electronics,
where gold has traditionally found use because of its good
resistance to oxidative corrosion.
Chemically, gold is a trivalent and univalent transition
metal. Gold does not react with most chemicals, but is attacked
by chlorine, fluorine, aqua regia and cyanide. Gold dissolves
in mercury, forming amalgam alloys, but does not react with
it. Gold is insoluble in nitric acid, which will dissolve
silver and base metals, and this is the basis of the gold
refining technique known as inquartation and parting.
Nitric acid has long been used to confirm the presence of
gold in items, and this is the origin of the colloquial term
acid test, referring to a gold standard test for
Where does the word gold come from?
The word gold appears to be derived from the Indo-European
root yellow, reflecting one of the most obvious
properties of gold. This is reflected in the similarities
of the word gold in various languages: Gold (English), Gold(German),
Guld (Danish), Gulden (Dutch), Goud (Afrikaans), Gull (Norwegian)
and Kulta (Finnish).
How much gold is there in the world?
The World Gold Council estimates that at the end of 2001,
it is estimated that all the gold ever mined amounted to about
Who owns most gold?
If we take national gold reserves, then most gold is owned
by the USA followed by Germany and the IMF. If we include
jewellery ownership, then India is the largest repository
of gold in terms of total gold within the national boundaries.
In terms of personal ownership, it is not known who owns the
most, but is possibly a member of a ruling royal family in
If gold is laid around the world, how far would it stretch?
If we make all the gold ever produced into a thin wire of
5 microns (millionths of a metre) diameter - the finest one
can draw a gold wire, then all the gold would stretch around
the circumference of the world an astounding 7.2 million times
Why is gold measured in carats?
This stems back to ancient times in the Mediterranean /Middle
East, when a carat became used as a measure of the purity
of gold alloys (see next Question 5). The purity of gold is
now measured also in terms if fineness, i.e parts per thousand.
Thus 18 carats is 18/24th of 1000 parts = 750 fineness.
What is Carat?
A Carat (Karat in USA & Germany) was originally a unit
of mass (weight) based on the Carob seed or bean used by ancient
merchants in the Middle East. The Carob seed is from the Carob
or locust bean tree. The carat is still used as such for the
weight of gem stones (1 carat is about 200 mg). For gold,
it has come to be used for measuring the purity of gold where
pure gold is defined as 24 carats.
How does a gold mine work?
The gold-containing ore has to be dug from the surface or
blasted from the rock face underground. This is then hauled
to the surface and milled to release the gold. The gold is
then separated from the rock (gangue) by techniques such as
flotation, smelted to a gold-rich doré and cast into
bars. These are then refined to gold bars by the Miller chlorination
process to a purity of 99.5%. If higher purity is needed or
platinum group metal contaminants are present, this gold is
further refined by the Wohlwill electrlytic process to 99.9%
What happens to gold after it is mined?
The ore is normally sent to a refinery, which will extract
and melt down the gold into a pure 24ct form, normally as
bars or ingots.
How big is a tonne of gold?
Gold is traditionally weighed in Troy Ounces (31.1035 grammes).
With the density of gold at 19.32 g/cm3, a troy ounce of gold
would have a volume of 1.61 cm3. A metric tonne (equals 1,000kg
= 32,150.72 troy ounces) of gold would therefore have a volume
of 51,762 cm3 (i.e. 1.61 x 32,150.72), which would be equivalent
to a cube of side 37.27cm (Approx. 1' 3).
What percentage of gold is used in jewellery, industry
Around 70% of gold demand is jewellery, 11% is industrial
(dental, electronics) and 13% is investment (institutional
and individual, bars & coins). Gold jewellery has strong
investment attributes in all countries, and in
markets such as India and Middle East is sold by weight at
the prevailing daily rate with a supplementary making
charge which varies according to the complexity of the