FREQUENTLY ASKED QUESTIONS
Purity refers to the amount (by weight) of pure gold an
object has. The most common way of describing purity, particularly in the
jewellery industry, is by Carats (Karat in the US). Carats are
just the purity expressed in units of 24, such that 100% equals 24 carat and
50% equals 12 carat.
For bullion, refiners and dealers use either percentages
or fineness (fine being another word for pure). The table below shows
the most common purities.
In wholesale investment precious metal markets, physical
gold is traded in bars of approximately 400oz with a purity of 99.50% or more.
The reason wholesale gold is traded at 99.50% is because it is much cheaper
to refine to this purity than 99.99%, which requires additional processes.
Australian gold bullion coins and bars are made from
99.99% pure gold. In verbal discussions, 99.99% is often referred to as
"four nines". You may also hear reference to 99.9999% gold - six
nines - the purest form of gold ever produced.
In 1957, The Perth Mint produced a gold proof plate of
almost six nines as measured by the Worshipful Company of Goldsmiths in
London. The Royal Mint was so impressed that it ordered some of the gold as
the benchmark for its own standards.
Image: The Perth Mint's Plate 42C - the purest gold
ever tested by the Royal Mint with certificate of verification.
