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GOLD
Pure
(24K) gold is too soft to be appropriate for everyday
wear; therefore, gold jewelry is made of a mixture of
gold and other metals (such as silver, copper, nickel
and zinc). The K (karat) number tells us what fraction
of 24 parts of the alloy are pure gold; ie., 14K is 14/24,
or 58.33%, pure gold. The metals used in the alloy also
determine the color of the gold; a greater percentage
of nickel gives white gold its color, while a high percentage
of copper lends a reddish tone to rose gold. While gold
itself does not tarnish, these alloying metals can sometimes
cause a piece to darken with time, or leave a dark residue
on the skin. In Europe, gold is marked with a number indicating
the gold content as parts per thousand; ie., 18K gold,
which is 75% pure gold, is stamped 750. |
PLATINUM
Platinum
is rarer, and therefore more expensive, than gold. It
is grayish-white in color, non-tarnishing, and very strong.Very
high temperatures are necessary to melt platinum; therefore,
it did not become a viable jewelry metal until advancements
in jewelers' tools were made in the late 1800s. It became
the most popular jewelry metal in America in the 1920s;
its durability made it the ideal choice for the lacy filigree
styles of the period. Jewelry platinum is an alloy, usually
90% platinum and 10% iridium. Platinum jewelry is typically
stamped "Plat." |
SILVER
Because
silver tarnishes easily and is less durable than gold
or platinum, it is not considered an ideal metal for setting
precious stones. However, until the introduction of platinum
and white gold alloys in the late 1800s and early 1900s,
silver was the only white precious metal available. It
remains popular as a jewelry metal because it is more
plentiful, and therefore much less expensive, than gold
and platinum. Sterling silver is 92.5% pure silver; such
pieces are often marked "SS," "Sterling,"
or "925." Coin silver is 90% silver and is sometimes
marked "900." German silver and nickel silver
are misnomers for alloys of other metals that contain
no silver at all. |
PALLADIUM
Palladium
is a member of the platinum metals group. It is harder,
lighter and less expensive than platinum. It was used
in jewelry manufacturing during WWII as a substitute for
platinum (which was restricted, being considered a strategic
metal). |
VERMEIL
Popular
in eighteenth century France, vermeil pieces were made
of sterling silver and coated with gold ("silver
gilt"). Production was banned in the early 1800s,
however, when it was discovered that the mercury used
in the process caused the craftsmen to go blind. |
PINCHBECK
Pinchbeck
is an alloy of copper and zinc, discovered by Christopher
Pinchbeck (1670-1732). It was popular in the eighteenth
century as a gold look-alike; ladies often had their favorite
gold pieces reproduced in pinchbeck to take with them
on their travels. Its popularity waned in the mid-1800s
with the legalization of 9K gold and the invention of
the electrogilding process. Pinchbeck is rarely seen today. |
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