Gold is a unique
metal. It is valued not just for its rarity, but also for
its range of lovely colours, the distinctive character of
its soft metallic glow, its resistance to tarnish, and its
easy workability. Gold is so soft and malleable that one-ounce
can be stretched into a wire 50 miles long, or hammered
into a sheet so thin it covers 100 square feet.
In its pure
form, gold is a shiny yellow metal and is relatively inactive
chemically. The chemical symbol for gold, Au, is from its
Latin name, aurum. With a specific gravity of 19.4, it is
also one of the heaviest of the common metals - more than
twice as heavy as silver or lead. Because gold is chemically
inert, it resists oxidation and other changes which diminish
the brilliance of other metals.
The story of gold
Countless
ancient artifacts attest to gold's popularity and versatility.
The most malleable and ductile of all metals, gold has invited
the highest skills of artisans and craftsmen all through
the ages. For thousands of years gold has been formed into
articles of ornamentation, into religious icons and talismans,
and, of course, shaped and formed into currency.
As a symbol of beauty, nobility and constancy, gold has
been cherished and even worshiped. Wars have been fought
and nations conquered for gold. It is because of its exceptionally
high value that gold, in all its forms; from the very beginning
has required accountability, a system of weights and a standardization
of purity. It is not surprising that the need to assay and
account for gold led to the invention of the first scales
and balances.
Standards
of gold
Legal regulations
governing the marking of gold jewelry began in England as
early as the year 1239. In that year, a law was enacted
which established a procedure for authenticating the purity
of the gold used in various articles of jewelry. The procedure
involved the use of an official mark, which was stamped
on the article at Goldsmith's Hall in London or at one of
several British government assay offices. These "Hall
Marks" started a practice, which has since been duplicated
in practically every civilized country of the world.
In the United
States, Congress passed the National Gold and Silver Marking
Act to govern standards of purity of these metals for the
jewelry industry. This law also included standards of purity
for gold alloys. This practice required articles such as
gold-filled and rolled gold plate to conform to federally
controlled standards.
The most recent
amendment to the Gold and Silver Marking Act was passed
in 1976. The key provision of this amendment tightened the
purity tolerances of the gold or gold alloys in articles
of merchandise, so that "...the actual fineness of
such gold or alloy shall not be less by more than three
one-thousandth parts than the fineness indicated by the
mark stamped, branded, en- graved, or printed upon any part
of such article." The amendment also requires the fineness
of gold solders to be not less than seven one-thousandths
less than the stipulated purity. The amendment significantly
narrowed the "minus" tolerance of karat gold,
which was previously set at ½ karat for gold articles
and a full karat for soldered pieces.
The amendment also stipulated
that the gold content of an article must be at least ten
karats for it to be called "karat gold."
The
karat system
In the karat system,
pure gold is expressed as "24 karats fine" (24K).
(Pure gold in commercial practice is 99.95 to fine, but
is nominally considered 100%.) The gold content of any gold
article depends on the proportion of' pure gold it contains.
The most popular types that are used in jewelry in the United
States are:
24 K 100% gold
(99.95 %)
18 K 18/24ths or 75% gold
14 K 14/24ths or 58.33% gold
10 K 10/24ths or 41.67% gold
