How to check the carat rate of your gold?

If you are thinking about buying a piece of gold, you have to consider a few points in order to assess the value.

You need to know the scrap value - the daily price of gold fluctuates - and also take the historic or antique value into account.

A valuable piece of gold jewellery, made by Cartier for example with have added value because of the design and craftsmanship of the piece.

So, leaving aside designer or antique jewellery how can you assess the carat (or karat) value of a piece of jewellery?
Especially if it does not have a British hallmark?

Remember that the purity of gold is described in units of 24 and refers to the purity and not the weight (as with gemstones).

Gold is always mixed with a base metal and unless it is fine gold (24cts) the actual gold content of a gold ring may vary a great deal between one and another although they may look the same.

The purest gold contains 24 carats and 1 carat of gold is 1/24. However the markings on gold rarely read 18 ct or 9ct for example and instead a number such as 375 or similar.

You can calculate this number into carat value by multiplying by 1000.
9 carats for example means that the purity of gold is 9/24 or 37.5% gold
Multiply 9/24 by 1000 and you get 375 (meaning 37.5) Gold items marked 375 is 9 carat gold.

It works both ways.



So divide 375 by 24% and you will find the carat value. It shows up as 90 (or 9ct) because the truth is that the 375 number is actually 37.5.

Carat value can tell you a lot about the origins of your gold as well as the value.

• 333 or 8ct means that the item is 33.3% gold content. Predominantly Eastern European. 
• 375 or 9ct. 37.5% gold content.  Mainly of British and commonwealth origin.
• 416 or 10ct.  41.6% gold. USA.
• 500 or 12ct. 50% gold sometimes used in non-British or commonwealth antiques.
• 585 or 14ct. 58.5% gold. Sometimes found in Asian pieces for the export market.
• 625 or 15ct 62.5%. This standard is no longer used but you may find it on vintage pieces pre dating 1935.
• 750 or 18ct. 75% gold and a widely used gold standard.
• 916 or 22ct. 91.6% gold content.
• 999 or 24ct. 99.9% gold content As pure gold as it gets.

Markings to beware of include EP or GP because the P stands for Plate so the gold content is only going to be a few microns thick and added on top of a base metal.

It may have the “look” but not the value. Likewise with rolled gold - an alternative description for gold plate.

You also need to be sure that your piece is not silver with a layer of gold plate so be careful if you come across something that has a number that looks convincing and sounds familiar.

Such as 800, 925 and 950 – very common silver purity numbers.








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What is a Carat?

The quality of gold is measured in carats. As everybody knows, the higher the carat the better the quality of the gold but how do you measure it and what does it mean?

The word carat comes from the Arabic word qirat and means seed pod or husk, traditionally used to weigh small quantities.

The Greeks used the same measure and found it was the equivalent of a Roman measurement, the siliqua. This was one 24th of a gold Roman coin – the solidus of Constantine.

Today for gold measurement, this idea of the 24 units lives on.
However the amount of carats contained in gold  does not relate to the weight of the gold, just the purity.

By contrast, diamonds and precious gemstones also measured in carats, refer to weight. A gemstone carat weighs 0.2mg.

Gold is a very soft metal and used alone it is far too soft for many applications such as jewellery, as well as being expensive.

For these reasons it is usually mixed with another metal such as silver, copper or nickel to increase the hardness.


 The content of the gold is measured in units of 24ths or carats, sometimes spelt karats.

If a piece of jewellery is 18 carat gold this means that it is 18 parts gold and the remaining 6 units are made up of another metal. For nine-carat gold, the majority of the metal is base metal with only 9/24 of gold. This equals 37.5% gold or 375 parts per 1000. The weight of the gold does not affect the carat value.

Fine Gold
The purest gold available is 24 carat gold, also called fine gold. This means that out of the 24 units of gold, the full 24 are gold. To be more precise,  .9995 parts per 1000  or 99.95% is gold.

If this is converted to carats, it would be 23.988 carats or more likely 99.9% because of the residual impurities found in the metal.

The Royal Canadian Mint produce a .99999 fine gold coin which is advertised as the world's purest gold coin. Gold bars and ingots are classed as fine gold if they are over .995 which is 23.88 carats.





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