The Origins of the Term ‘Carat’
Carat is a measurement of mass we use for diamonds and other precious gemstones. It is also used to describe the percentage of pure gold in the metal alloy mix of jewellery.
The word Carat derives from French, Italian & Arabic and translates to the word bean-pod, more specifically the carob bean.
Carat Measurement in Gemstones
Throughout early history, carob seeds were used as a comparative measurement to determine the mass of a gemstone. It was believed there was little variance in the seed size, therefore they were considered a perfect object for measurement.
1.
It wasn't until 1907 that the 'carat' was officially adopted as a unit of measurement. Today carat weight has been globally standardised, with 100 carats equating to 20 grams. The carat remains a universal form of measurement for the mass of a gemstone. It is important to note that the carat weight of a stone does not necessarily determine the surface size of a stone. Gemstones with similar size face measurements can vary in their depth and weight. It is always best to view a gemstones surface dimensions when understanding what your stone might look like.
Carat Measurement - Gold
The carat measurement in regards to gold refers to the percentage of pure gold mixed together with alloy metal. As gold in its pure form is incredibly soft, it is alloyed with other metals to generate hardness. Gold carat is a measurement out of 24 - with 24 being pure gold. Therefore, 9ct yellow gold is 9 out of 24 parts pure gold.
While we now understand carat gold as an indication of percentage of gold in a piece, the origins of this measurement came from the early usage of carat weight.
2.
The medieval coin known as a the Mark had a carat weight of 24. To create these coins, pure gold was alloyed with other metals to help hold their shape. The purity of gold in each coin was then expressed through the carat weight of gold present in each coin.
Pictured above, a coin dated 42BC, Northern Greece.
1. Carob seed & seed pod
2. A Northern Greek coin dated 42BC