|
Karat
Content
of Gold
and Gold Alloys
Gold
quality is determined by karat content or fineness, and each karat
is 1/24th part of the entire substance. Pure gold is 24 karats,
and as it is alloyed with other metals, the gold content
decreases. For example, 18k gold is 18 parts pure gold and 6
parts of alloy metals; 14k gold is 14 parts pure gold and 10 parts
other metals.
Red
or pink gold (also called rose gold) contains large percentages of
copper and a small amount of silver in addition to gold. Green
gold is usually gold alloyed with additional silver or with silver
that has a small percentage of copper. White gold is primarily
75% gold with the balance nickel, or both nickel and zinc. Gold
alloyed with silver alone minus nickel or zinc will be less hard than
a nickel and zinc alloy and also a lighter yellow color.
Copper
alone added to gold makes the pure gold harder and more difficult to
work; therefore, some percentages of copper and silver are usually
combined in the alloy. White gold- formerly made of an alloy
consisting of gold, silver, and/or palladium (from the platinum
family)-is now also alloyed with nickel, copper, and zinc to produce
more ideal melting characteristics. |