Gold Markings and Purity Ratings

In the United States gold purity markings are as follows:

24K gold                =          100% pure gold

22K gold                =          91.7% pure gold

20K gold                =          83.2% pure gold

18K gold                =          75% pure gold

16K gold                =          66.6% pure gold

14K gold                =          58.3% pure gold

12K gold                =          50% pure gold

10K gold                =          41.7% pure gold

8K gold                  =          33.3% pure gold

The minimum karat marking that can be referred to as “gold” is 10K.
16K gold is used only in the dental industry.

European gold purity markings are as follows:

750             =          18K gold equivalent  -  75% pure gold

585             =          14K gold equivalent  -  58.5% pure gold

417             =          10K gold equivalent  -  41.7% pure gold

375             =            9K gold equivalent  -  37.5% pure gold

24K gold is pure 100% gold and is considered too soft for practical use in the making of gold jewelry.

24K or 22K gold was however commonly used in the decorating of vintage glass and porcelain pieces. It is still being used today on more expensive crystal and china. If you have gold trimmed china or gold trimmed crystal stemware, we recommend that it be hand washed. It really should not be put in a dishwasher.

You may see the term “gold encrusted” used on some vintage pieces. This usually means the gold is thicker and sometimes the gold itself has a decorative pattern to it.

In jewelry, which includes vintage jewelry, gold filled is readily available. A common marking for gold filled is “1/20 12K Gold Filled”. This means that 1/20th of the composition of the piece is 12K gold. This is a step up from gold plating.

Black Hills Gold is a style believed to have been developed in the 1870’s by Henri LeBeauold, a French goldsmith. All Black Hills Gold boasts a design of grapes, vines and leaves. It consists of green, rose and yellow gold and is always produced in the Black Hills of South Dakota.

Green shading is created by adding some silver to the gold and rose shading is created by adding copper. Gold is always mixed with another metal to give it strength.  It is how much of the other metal that determines the karat content of the gold.

Gold plating is frequently used in the making of fashion or less expensive costume jewelry. A piece of jewelry is made out of another metal or alloy and a coating of gold is then applied over it. The thickness of the coating pretty much determines how quickly the gold layering will or will not wear off. Some companies that make gold plated jewelry advertise that their techniques are special and the plating will not wear off. I’ve never seen a piece where the gold has not worn off eventually. Gold plate marks are GE, HGE, GP and EP.

Gold coins and gold bars are also not 100% 24K gold. Most gold coins and bullion (bullion coins or bullion bars) are either 99.9% or 999.99% pure gold. The balance is another stronger alloy.

Some of the alloys used with gold and the effect those alloys have are:

Silver = gives a green tint
Zinc = gives a bleached look
Copper = gives a red tint
Nickel  = gives a white look
Palladium = gives a white look

If you are buying gold bullion such as gold bars, the price is always based on the weight of the gold. Sometimes it is measured in grams but usually it is in ounces. When you see the weight in ounces be sure to find out which type of ounce is being quoted. There are two.

There is the troy ounce and the avoirdupois ounce. A troy ounce is exactly 31.1034768 grams. The avoirdupois ounce is exactly 28,349523125 grams. There are 12 troy ounces to a troy pound and 16 avoirdupois ounces to an avoirdupois pound. The troy ounce is heavier than the avoirdupois ounce. It makes a big difference in the price.

Just as a point of information, although the troy ounce is still very instrumental in measuring gold and other precious metals today, the troy pound is no longer in use.

Other weights used in measuring gold are grains, grams and pennyweights. Pennyweight is also referred to as “dwt.”

Here is how they breakdown:

24 grains to 1 pennyweight = 1.5552 grams
1 gram = .64 pennyweight
1 pennyweight = 1.56 grams
20 pennyweights to 1 troy ounce = 31.1034768 grams
12 troy ounces to 1 troy pound = 373.24 grams

Written by Anne Benedetto, Auction House Talk
 All Rights Reserved

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