Understanding Gold, Silver and Platinum Markings on Jewelry

[Steve in PR]

Most jewelry will have a marking (Hallmark) on it showing its purity or content of a precious metal.

Not every piece is marked. Sometimes the mark is removed as a result of the item being resized or it is worn out. Some items are not required to be marked because they are a purity that falls below the industry standards for marking.

Gold is not the most precious metal. Platinum is more valuable than gold on a weight basis. It is rarer and more expensive to mine.

I will start with gold because it seems to get the most questions about how to interpret its purity.

GOLD

We are pretty familiar with the term 24 Karat as meaning pure or genuine. The purity of gold is based on 24 Karat representing 99.99% purity of gold.

Every other marking represents a fraction or percentage of purity.

18 Karat represents 18/24ths. Reduce this to a common fraction and it becomes ¾ or 75%.

So, 18 Karat is 75% pure gold. The rest of it can be a mix of other metals such as silver rhodium, copper and/or nickel. The mix determines the color of the gold. White gold, for example, will have a little nickel added to give it its "white" color but if it is marked 18 Karat it still contains 75% gold.

Here is a breakdown of the Karats ratings (More common ratings are in bold):

24 Karat = 100% gold
23 Karat = 95.8% gold
22 Karat = 91.6% gold
21 Karat = 87.5% gold
20 Karat = 83.3% gold
19 Karat = 79.1% gold
18 Karat = 75.0% gold
17 Karat = 70.8% gold
16 Karat = 66.6% gold
15 Karat = 62.5% gold
14 Karat = 58.3% gold
13 Karat = 54.1% gold
12 Karat = 50.0% gold
11 Karat = 45.8% gold
10 Karat = 41.6% gold
9 Karat = 37.5% gold

Below 9 Karat, gold might not be marked for its purity.

Europe uses a system based on 1000 to mark their jewelry.

24 K = 1000 fine
18 K = 750 fine
14 K = 583 fine
10 K = 417 fine

For more detailed information go here:

Gold Info Weight Measure Units-Gold Calculator Software


SILVER

Silver markings are similar to gold’s.

Most silver jewelry manufactured in modern times will contain a marking of 925.

This represents 92.5% pure silver and the rest is usually copper.

It is also the minimal purity for an item to be called "Sterling" silver.

For more detailed information go here:

Silver Info Weight Measure Units-Gold Calculator Software


PLATINUM

The amount of platinum in a product is expressed in parts per thousand. "Pt1000" means that the product is 100% pure platinum. "Pt850" means that it is 85% pure platinum and 15% platinum alloy.

Platinum content is usually marked as "950Pt", "950 Plat", or "Plat".

In the United States, in order to be marked "Platinum" or "Plat", a piece of jewelry must contain at least 50% platinum.

For more detailed info go here:

Platinum Info Weight Measure Units-Gold Calculator Software