Gold, Platinum and Palladium
Sought after by explorers, this element is
the most widely desired metal in modern jewelry manufacturing.
Gold, whose atomic symbol is Au on the periodic table of elements,
is naturally yellow in color. The specific gravity of gold is 19.3+,
which is quite heavy for metallic minerals. One quality of gold
is that it is easily formed into various shapes. This has made
it a premium choice for jewelry artisans throughout the centuries.
Gold in its purest form is defined as 24 karat. Pure gold is too
soft for most jewelry uses, so it is mixed, or alloyed, with other
metals to alter its properties and color. It is common to see gold
jewelry in 18k or 14k. This represents an alloy that contains 18/24
or 14/24 parts gold in the overall mix. This value could also be
expressed in percentages of purity as 75% for 18k and 58.33% for
Platinum, whose atomic symbol is Pt on the periodic table of elements,
is naturally gray, or silver in color. The specific gravity of platinum
is 21.5, which is heavier than gold. Platinum for jewelry, as opposed
to gold, is used in a nearly pure alloy, which makes for a much heavier
piece than the same design made in gold.
Platinum is easily formed
into various shapes, and it is usually mixed, or alloyed, with other
metals such as gold, nickel, iridium, palladium, rhodium, or ruthenium
to alter its properties. Platinum will cost approximately 2-4 times
as much as the same piece of jewelry made in gold. This is due to
the density of platinum as well as the extreme heat and techniques
required for its manufacture.
Palladium itself has been used as a precious metal in jewelry since 1939, as an alternative to platinum or white gold. This is due to its naturally white properties, giving it no need for rhodium plating. It is slightly whiter, much lighter and about 12% harder than platinum. Similar to gold, palladium can be beaten into a thin leaf form as thin as 100 nm (1/250,000 in).
It can also be used as a substitute for nickel when making white gold. Palladium is one of the three most popular metals used to alloy with gold, making white gold. (Nickel and silver can also be used.) Palladium-gold is a more expensive alloy than nickel-gold, but it's naturally hypoallergenic and holds its white color better.