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Explore the secrets of diamonds

When you think of gold jewellery, the first image that comes to mind is certainly that of a jewel set with diamonds and full of sparkle. Of all gems, diamonds are the most prized and precious. If diamonds are so famous today, it's because of their history, but also because of their properties.

The origin of diamonds

The first diamonds were found in India over 3,000 years ago, close to rivers in the Golconde region. It remained the diamond mecca for centuries. India and Indonesia remained the only places where diamonds were mined until 1725. The discovery of America also led to the discovery of large diamond deposits in Brazil.

The word diamond comes from the ancient Greek "adámas", meaning "indomitable". The hardest material in the world, diamonds have always been a complex material for lapidaries to master. Diamonds are highly prized by jewellers. They are made of crystallised carbon, and contrary to what you might think, they come in a wide range of colours.

Diamond classification

Diamonds are classified according to several characteristics. In the trade, these are known as the 4Cs of diamonds. These 4 criteria determine the rarity and price of a diamond.

C for "Cut

Cutting a diamond is one of the most important things you can do. It's how a diamond reveals its brilliance and disperses the rainbow spectrum of light. Because of its great hardness, a diamond must be cut and polished exclusively by another diamond. The main diamond-cutting centres are currently located in Antwerp, Belgium, and Tel Aviv, Israel. The most common cut is the "brilliant" cut, which brings out the diamond's natural brilliance to the maximum.

C for "Color

Diamond colour is a very important characteristic for many jewellery customers. Diamonds are graded on a scale from D to Z, with D being the best quality with a very pure white colour, and Z being the worst quality with a very pronounced colour. This classification is only valid for white diamonds. Other diamonds known as black are graded differently.

C for Clarity

Diamonds, like most other gems, contain inclusions. An inclusion is an impurity; they generally appear in the form of dots or spots that are rarely visible to the naked eye. Diamonds are therefore also graded according to the visibility and number of these inclusions:

  • IF / FL: Absence of internal and surface inclusions at 10x magnification
  • VVS1 / VVS2: Tiny inclusion(s) very difficult to see with a magnifying glass at 10x magnification
  • VS1 / VS2 : Very small inclusion(s) difficult to see with a magnifying glass at 10x magnification
  • SI1 / SI2 / SI3 : Small inclusion(s) easily visible with a magnifying glass at 10x magnification
  • I1 / I2 / I3: Large and/or numerous inclusions visible to the naked eye

C for Carat

Caratage refers to the weight of a diamond and is without doubt the best-known criterion. 1 carat is equivalent to 0.20 grams. The name carat comes from the name of the seed of the "kuara" tree. This seed has the particularity of always having the same weight. It was therefore widely used in the gold and diamond trade. It is also the criterion that most influences the price: the value of a diamond is exponential according to its caratage. A 2-carat diamond will not be twice as expensive as a 1-carat diamond, but much more, since they are rarer and the loss during cutting is higher.


At Thea Jewelry, we use HSI quality stones for all our diamond-set creations. This quality offers a perfect balance between colour, clarity and cut. HSI diamonds are diamonds that have a slight tint of colour, inclusions visible under magnification (x10), but are well cut to maximise their brilliance. These diamonds offer excellent value for money, as they look good without the higher cost of diamonds with no tint and no inclusions.


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