The 4Cs of Diamond: Carat

Diamonds are precious stones of inestimable value, so important and special that they are evaluated according to 4 "Cs": carat, purity, color, cut.

Today we look at the first of the 4cs together: what are carats?

First of all

A carat is a unit of measurement , used in metallurgy and goldsmithing to define the mass of precious materials. It can also be an indicator of purity of gold alloys.
Weight, expressed in carats, is the measure of the mass of a diamond. One carat corresponds exactly to 200 milligrams.

The story

The carat has been used as a unit of measurement for weighing very small quantities since ancient times. After the Middle Ages, it remained the unit of weight measurement for everything related to the world of precious stones. It is therefore applied to diamonds, stones and gems and to the purity value of gold.

The actual definition of the weight of a carat was defined in 1832, in South Africa . The region, at the time, was the place of greatest production and export of diamonds in the world. It was there that the exact relationship between carats and measures of the decimal metric system was established: some carob seeds were weighed on a balance with equal arms, to perform an arithmetic mean with the measured diamond: the value was approximately 0.2 grams. The value of the carat was made official in 1907 , at the Conference Generale des Poids et Mesures.

1 Karat or Carat = 0.2 Grams

The name

The word derives from the Arabic qīrāṭ , meaning "twenty-fourth part". The Arabic word appears to derive in turn from the Ancient Greek κεράτιον (kerátion), referring to the carob seed, which was believed to always have a constant mass.

In reality, the mass of these seeds varies, as happens with all seeds in the world. However, it was used since ancient times as a comparison measure because it was easy to see the difference in size with the naked eye, thus choosing seeds that had the same weight.

Carat and gold

As regards gold alloys , the term carat takes on a different meaning from the unit of weight measurement typical of gems and pearls, becoming a measure of purity , which quantifies the parts of gold in an alloy on a 24/24 basis. A carat, therefore, when speaking of gold, means the part of gold out of a total of 24 parts of metal, constituting the alloy. The gold of maximum purity is therefore 24 carats.

Why is the reference number for purity 24? There is an explanation for this too: it comes from an ancient pure gold coin used thousands of years ago in Germany. This weighed 24 carats, or 4.8 grams. Its composition and weight were taken as a reference point for evaluating the purity of gold jewelry.

A 24 carat jewel (generally expressed as 24K) is the purest on the market, because it corresponds to 999.9 grams of gold in 1000 grams. This type of gold is not used because gold is soft and tends to deform easily.

Below are other acronyms that can be read engraved on a jewel. The most common, from the most valuable and expensive are:

• 22 Kt (916,667/1000) – + 90% gold
• 18Kt (750,000/1000) – 75% gold
• 12 kt (583.333/1000) – 50% gold

Most of the gold jewelry we find in the European area is 18 Kt, where gold is 75%. According to the Law, every gold jewel should have on its surface an engraving that indicates the name of the manufacturer and the carats: which in the case of 18K is equal to 750.

Carat is the unit of measurement that characterizes the weight of a diamond. The more carats it contains, the more valuable the diamond in question!