Here in the U.S. ‘Karat’ with a ‘K’ is a measure of gold’s purity, whilst in other parts of the world it is spelt as ‘Carat’ with a ‘C’.

Because pure gold is naturally a soft, malleable metal, it is alloyed with other elements to strengthen it, which in turn can affect its color and cost.   Much of today’s gold is mixed with a percentage of alloys – metals that modifies the color of gold and makes it harder and stronger.   The karat mark in your gold jewlry tells you the percentage of pure gold to alloy.  The higher the karat quality the greater the proportion of gold it will contain.    So be sure to ask you jeweler to show you a selection and see what karat gold you are interested in.

The word ‘karat’ comes from Arabic, meaning “bean seed”, because years ago seeds were used to measure the weight of gold and precious stones.   Now though karat means the amount of gold an item of jewellery contains.   For example, pure gold is 24 karat or 99.9% pure – depending on the style, this might be quite soft, and so an alloy is added.

The higher the karat quality the greater the proportion of gold it will contain.  
Countries across the world allow different minimum karat standards.   For example, in France and Italy the lowest permitted standard for gold is 18 karat.   In the UK it is 9 karat, in Germany it is 8 karat, and in the USA, it is 10 karat gold.

Want to know more?   This table provides the various karatages and their equivalent gold content in percentage and fineness terms, as recognised by international standards which you might find useful.

Definition of karatage in gold content for recognised international standards

Carats / Karats Fineness (of 1000) Gold, % content Comments
24 999 99.9% Pure gold
24 990 99.0% Minimum allowed for pure gold
22 916 91.6% Indian subcontinent
21 875 87.5% Arabic countries
(19.2) 800 80.0% Standard in Portugal
18 750 75.0% Standard international Karatage
14 585 58.5% 583/58.3% in USA
10 417 41.7% Minimum in USA
9 375 37.5% U.K. standard
8 333 33.3% Minimum Germany