Terminology:
- 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 (not common anymore), silver, or palladium.
- EPNS—It stands for “Electroplated Nickel Silver,” which is silverplate. This means the piece is not gold, and it’s worthless.
- EPBM—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 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 41.7% pure, or 10K. In the US, jewelers uses this purity because it is very strong. It is great for jewelry for those who work industrious jobs or who need something that will hold up.
- 585—This means that the gold is 58.5% pure, or 14K. Good, strong gold but with more gold than 10K.
- 750—This means that the gold is 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 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’s highly rare to find it so pure. Such fineness in gold was last refined in the 1950s by the Perth Mint in Australia.
| Karats | Parts of Gold | % of Gold | Purity Fineness |
|---|---|---|---|
| 9K | 9/24 | 37.5 | 75 |
| 10K | 10/24 | 41.7 | 416/417 |
| 12K | 12/24 | 50.0 | 500 |
| 14K | 14/24 | 58.3 | 583/585 |
| 18K | 18/24 | 75.0 | 750 |
| 22K | 22/24 | 91.7 | 916/917 |
| 24K | 24/24 | 99.9 | 999 |