Understanding Gold Purity: 9K, 10K, 14K, 18K, 22K, 24K, etc…..
The stamp on this piece of gold could indicate what use it’s intended for and how many, if any, other metals were added to it. Many of us, at one point or another, will sell gold we bought from a jewelry department of a department store, or jewelry store. If you’ve ever gone shopping for jewelry, you are probably familiar with the word “karat” as applied to gold. The higher the karat, the more expensive it will be. But have you ever wondered why? The short answer is that higher karats mean more gold, but there is more to it than that.
What Are Karats?
Karats, are the little numbers stamped on a piece of gold in the format of “xxK” or “xxKT”. The numbers refer to the type of gold and to the actual gold content in the particular piece of jewelry.
Here’s more information on karats:
- Karat is a measurement of the ratio of gold to other metals or alloys.
- Karats are measured on a scale from 0 to 24.
- The higher the karat number, the more gold there is and the less other metal content.
- Other metals and alloys could include copper, nickel, silver, or palladium.
24-karat gold is the purest gold you can buy. Gold is malleable in its pure state. Other metals are added to strengthen it and in some cases to enhance color.
How to Use Karats to Measure Gold Purity
Here is how to use the number of karats to figure out how pure your piece of gold is. If you purchase a ring that is 14K gold. Since the number amount of karats you can have is 24K, divide the 14 Karats by the 24. You will get .583. This means that the gold is 58.3% pure in a perfect world. In reality jewelry gold purity can very 10 to 20% (usually to the down side).
Gold Purity Terminology
- Assay: A test which determines metal content and quality.
- Bullion: Precious metals in a bulk, uncoined form such as gold bars, considered in mass rather than value.
- Carat: Not to be confused with Karat in, a Carat is a unit of measurement used for precious stones.
- Ductile/Ductility: How capable a metal is to being deformed using tensile force. Ex. Ductile materials can be stretched into thin wires without fracture.
- Hallmark: A symbol or mark stamped on a piece of precious metal which certifies its standard of purity.
- Karat: Unit of measurement for the fineness of gold, with the higher numbers containing more gold and 24K being the finest.
- Malleable/Malleability: How capable a metal is of being deformed using compressive force. Ex. Malleable metals can be hammered or rolled into thin sheets.
- Millesimal Fineness: A system used to show the purity of precious metals by parts per thousand rather than karats.
- Troy Ounce: 31.1034768 grams, or approximately 1.09714 standard “avoirdupois” ounces.
- Troy Weight: A system of measurement used for gemstones and precious metals, where a full Troy Pound consists of 12 “troy” ounces rather than the 16 “avoirdupois“ ounces in a standard pound.
What Do the Stamps on Gold Mean?
Here’s a list of stamps you might find on a piece of gold and what they mean.
- EPNS If someone is trying to sell you a piece of “gold” marked “EPNS,” run away. It stands for “Electroplated Nickel Silver” which is silverplate. This means the piece is not gold, and it’s worthless.
- EPBM Again, if someone is trying to sell you “gold” marked “EPBM,” go elsewhere. This stands for “Electroplated Britannia Metal” which is not gold at all. It is a silver/tin alloy consisting of copper, lead, or zinc.
- GE: Gold Electroplate This is a piece consisting of a base metal, often brass, with a certain thickness of gold electrolytically deposited onto the base. The minimum standards require to be considered GE is 7 millionths of an inch and at least 10K gold as the plating.
- HGE This also refers to Heavy Gold Electroplate, the same as GE above, but it can only make the “heavy” classification if the plating is at least 100 millionths of an inch.
- GF This means Gold Filled and is like gold plate but the gold is heat- and pressure-bonded to the base metal. It must have a minimum purity of 10K gold and the gold content must be at least 1/20th of the weight of the metal piece.
- 375 This means the gold is 37.5% pure, or 9K. In the US, the minimum standard for gold is 10K. Many other countries allow marketing this as gold and it’s been used in both jewelry and dental applications.
- 417 This means that the gold is sold as 41.7% pure, or 10K. In the US, jewelers uses this purity because it is very strong.
- 585 This means that the gold is sold as 58.5% pure, or 14K. Good, strong gold but with more gold than 10K.
- 750 This means that the gold is sold as 75.0% pure, or 18K. Much more pure than 14K, still has good strength with a wonderful balance in purity.
- 916 This means that the gold is sold as 91.6% pure, or 22K. This is probably the softest and most pure gold you would want to have for a piece of jewelry.
- 999 This means the gold is 99.9% pure, or 24K. This is the purest that you can buy, and although purity can be up to six nines fine, or 999.999, it is highly rare to find it so pure.
Gold jewelry is not usually pure gold. It is an alloy; a mixture of metals. Gold jewelry can be alloyed with silver, copper, zinc, palladium, and nickel to create different gold colors. The most common gold colors are: yellow, white, rose, and sometimes green.