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Home  Information Jewelry Learn about Precious Metals
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Learn about Precious Metals |
Precious metals have been a part of human civilization for thousands of years. Often believed to have mystical powers, precious metal was most attractive as a measure of value (money) and for its beauty. Over time, precious metals came to symbolize wealth, power and strength.
Eight metals are considered precious: Gold, Silver, and the six member of the the Platinum family - Platinum, Palladium, Rhodium, Ruthenium, Iridium, and Osmium. The National Gold and Silver Marketing Act, first passed in 1906, requires that the manufacturer's hallmark (registered trademark or trade name) be stamped on an item if a quality mark is used.
GOLD
Throughout history, gold has been the foundation of many monetary systems and
remains important to our economy today. Gold is also a popular metal of jewelry
designers because of its versatility. It can be molded, shaped and carved into
intricate jewelry designs. Its warm color is very appealing, and it doesn't
rust, tarnish or corrode. The major source of the world's gold is South Africa.
Pure gold is so soft that it is rarely used in jewelry, but rather is mixed
with another metal - usually copper or silver - to make a stronger gold alloy,
or mixture of metals. The amount of pure gold in an alloy is expressed in
karats (versus the carat weight used for measuring diamonds and other gems).
The higher the percentage of pure gold, the higher the karat. Pure gold is 24K,
while 10K gold - the minimum that may legally be called karat gold in the United States - is 10 parts gold to 14 parts other metal. The standard is 14K in the United States, 18K in Europe, and 22K in India, Japan and some other Asian
countries.
"Solid gold" refers to an item that contains some gold (at least 10K)
and is not hollow. "Gold-filled" is a process by which a layer of
gold (at least 10K) is mechanically bonded to a base metal.
"Gold-plated" means that an item has a plating (or coating) of gold
alloy of at least 10K, though usually less gold than in gold-filled items.
As the karat weight drops, the metal becomes more durable but less yellow.
Sometimes gold that is a lower karat weight will be plated in high-karat gold
to enhance the color. This is perfectly acceptable as long as you pay a fair
price. Keep in mind that gold plating will wear off with time, and the jewelry
may need to be re-plated.
The surface of gold jewelry is treated in many ways to enhance the design.
Styles like satin, brushed or matte that create soft, lustrous looks to a
hammered finish that produces a bright, irregular surface texture offer
consumers a variety of looks.
 WHITE GOLD
White gold has the same properties as yellow gold, but it has been mixed with
different metals to give it a white color. Instead of the copper and silver
used in yellow gold, white gold contains metals like nickel, zinc, or even
platinum. However, white gold should not be confused with platinum, which is
much rarer than gold and hence more valuable.
The same karat weight system is used for both white gold and yellow gold. While
18K yellow gold and 18K white gold contain the same proportion of gold; only
the remaining 25 percent of the alloy is different. Sometimes white gold is
plated with an even whiter metal, such as rhodium (a very rare member of the
platinum family), to enhance its appearance.
White gold was developed to give a different look to jewelry. The white color
is an excellent setting for very white diamonds, and when used side by side
with yellow gold, it creates a striking effect. Jewelry using both white and
yellow gold is called "two-tone."
 PLATINUM
The most precious metal used in jewelry is platinum. Heavier, more rare and
more durable than gold, platinum is very expensive and is alloyed with other
precious metals for added strength. Platinum jewelry is usually produced from
an alloy of 90 percent platinum and 10 percent iridium, two of the precious
metals in the platinum family. The other members include palladium, ruthenium,
osmium and rhodium (also used for plating because of its extreme whiteness).
Because of its purity, platinum is excellent for people who are allergic to
other metals. Platinum will never tarnish or wear out, and its light color
makes it popular for jewelry. Like white gold, platinum settings make white
diamonds appear very bright; however, platinum is whiter in color and heavier
than white gold.
Used extensively in jewelry throughout the first half of the 20th century,
platinum was banned for use in non-military applications during World War II.
However, it has enjoyed an enormous resurgence in popularity in recent years.
Mined in Africa, Russia and the United
States (Montana), platinum is not sold according to karat weight. Platinum jewelry that is stamped with a quality
mark also shows the percentage of platinum used in the alloy - for example, Pt1000, 1000Pt or 1000Plat for pure platinum; or Pt950, 950Pt or 950Plat for 950 parts per thousand platinum and 50 parts other metals.
 SILVER
The standard for sterling silver has remained unchanged since 1300 when Edward
I of England established an early trade practice rule for silversmiths, decreeing
that sterling must consist of 92.5 percent pure silver alloyed with 7.6 percent
copper. The term "sterling" refers to the composition of the metal,
never to the weight of a finished item.
Silver is much more plentiful than gold; however, silver tends to tarnish,
making it less popular in some forms of jewelry. Like gold, silver is too soft
for use in its pure state and must be combined with other metals for
durability.
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