INFORMATION FOR GOLD ESTATE JEWELRY
For centuries, gold has been a precious metal used for making gold jewelry. Gold has a beautiful color and is very malleable and ductile.
When in the air pure gold is resistant to oxidation. Pure gold is will not tarnish, however, if the gold is not pure tarnishing may occur.
The chemical symbol for gold is Au and the melting point is 1064 degrees C. Pure gold is found in nuggets, grains of flakes. Rarely are large amounts of gold found. Gold is initially found by mining, panning and the washing away of soils that have gold.
The word karat used to determine gold content comes from the Arab name for licorice, "kharrub", the hard seeds were usually of the same weight and were used to measure weight for precious metals.
Every country has a different system for hallmarking gold.
In the United States, the purity of gold is designated by karat. Pure gold is 24K, however, 24K gold is seldom used to make jewelry. Pure gold is too soft and will not the designed shape and gemstones will fall out. Most gold used for jewelry is actually a gold alloy with the use of other metals added to strengthen the metal or give it another color. Metals like copper, silver, zinc and nickel are added to enhance the strength of the metal. The percentile of metal added will determine the karat of gold. Vintage gold rings marked with "KP" would indicate that the gold is "Karat Plumb" or a true 14KT. This is based on US gold regulations passed in 1978 that gold may only vary within 1/2 of a karat to qualify for a KT marking.
In Europe, gold is stamped according to its fineness. Gold stamped "1000" is considered pure gold. 750 is the mark for 18K gold, indicating that the gold content is 75 per cent pure gold.
In England, estate jewelry may be marked "ct" for karat with a "c" instead of a "k", this hallmark was used form 1789 to 1975.
It is not correct to measure the purity of gold used in estate jewelry, antique jewelry or vintage jewelry solely based on a gold hallmark. Many pieces of estate jewelry were never hallmarked and many gold jewelry hallmarks have worn off with wear and use. Often gold marks are inaccurate.
CORRESPONDING US and EUROPEAN FINESS GOLD HALLMARKS USED in ESTATE JEWELRY AND VINTAGE JEWELRY
|EUROPEAN FINESS MARKS
||PERCENTAGE of GOLD
GOLD COLORS IN ESTATE JEWELRY
Two factors determine gold color. One is the alloy used to mix with the gold and the other is the percentage of the alloys used.
Yellow Gold is the natural gold color.
BRIGHT YELLOW GOLD
Pure gold mixed with copper, nickel and zinc.
Pure gold is mixed with a large percentage of silver, along with nickel and zinc to alter to color to white. 18K, 750 white gold has a slightly yellowish color if not enough silver is added. In order to get a shinny white color sometimes estate white gold rings have been plated with rhodium. During the 1920s and the 1930s, white gold became very attractive to compete with platinum jewelry. Many estate engagement rings and antique filigree engagement rings of that period were made with 14kt or 18kt white gold. Belais is the first company to obtain the patent for white gold in the 1910s.
ROSE GOLD or PINK GOLD
A large percentage of copper is mixed with pure gold to create the rose color. Estate rings made with rose gold or pink gold were made frequently in the 1940s "Retro Modern Jewelry Period." These jewelry period pieces are gaining new popularity.
Pure gold mixed with fine silver, copper and zinc. Green gold, and often gold made of three colors may be an indication that an estate jewelry piece may be from the 1940s "retro modern jewelry".
An alloy of gold and aluminum, usually consisting of 18 to 6 parts. It is not a pure purple, but is a bronze color with a touch of blue-plum. Purple gold was a very popular jewelry color in the late 1930s.
An alloy of gold and steel, once widespread in Europe.
Pure gold mixed with a higher percentage of copper.
ROLLED GOLD PLATE
Jewelry marked 14K R.G.P. is not 14 karat gold. The R.G.P. stands for "rolled gold plate", which is applying a layer of gold alloy to a layer of base metal. Antique rings, necklaces, and pins made of rolled gold plating were very popular in the 1800s and 1900s. This type of antique jewelry may also be marked "rolled gold plate."
Jewelry marked 14K H.G.E. has been gold plated or "hard gold electroplated". Meaning the piece of base metal has been plated with a thin coating of gold by an electrical process.
Jewelry marked with 14K G.F. indicates that the jewelry is "gold-filled". The jewelry is not "gold-filled", but is made by joining a layer of gold to a base metal as in rolled gold plating. There is more gold in gold-filled than in rolled gold plating.