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Goldschmied Primus - your expert for diamonds

Josef Primus completed his training as a diamond appraiser in 1975 at the German Gemmological Society (German Society for Gemstone Studies) e.V. in Idar-Oberstein (Germany). He has perfected his knowledge due to his more than 40 years of experience as a diamond appraiser.

Goldschmied Primus is your competent specialist for diamonds of unique quality and the finest texture. You can buy individual stones as well as diamond-set jewellery from us. Our experts would be happy to explain the 5 Cs to you!

The diamond - an eternal symbol of love  

Up until the 15th century, only kings wore diamonds as a symbol of strength, courage and invincibility. Over the past few centuries, however, the diamond has become a unique gift of love.

The term diamond has been documented as Middle High German "dīamant, dīamante and dīemant"  since the 13th century. It is based on a combination of ancient Greek: "a" (against) and "damnánai"  (defeat, conquer), in Greek: "adámās"  steel, very hard material, diamond, which meant "insurmountable" and indicated the hardness of the crystal; it found its way to Latin: "adamas,  adamans" (steel, diamond and the old French: "diamant"), and finally to German.

Beginning a word with "dia" came first in Romanic languages, based on Greek: "diaphaínein" (to shine), to differentiate it from the meaning "metal". In classical Latin, as in Greek, particularly hard materials were referred to as “adamas”. Although the diamond is considered the hardest of all substances, its structure is extremely simple. It's made of ordinary carbon - like graphite in a pencil, but has a melting point of 3816 degrees Celsius (two and a half times higher than that of steel). In a previously unfamiliar process, billions of years ago, under enormous heat and pressure, carbon crystallised into diamonds in the melting pot of glowing lava deep inside the earth. This crystallised carbon was carried to the surface by the so-called pipes, broke through the mantle of the volcano and cooled down in the kimberlite chimneys on the earth´s surface.

These chimneys are the main sources of discovery for diamonds today.  The origin of diamonds is in India, where mining first occurred. In 1869 the first diamond was found in the kimberlite bedrock in Kimberley (South Africa). In 1955 the first diamond was artificially produced. In 1961 the first diamond was discovered on the ocean floor. An uncut diamond often looks so similar to a pebble that most people would not be able to tell it apart straight away. However, it depends on the skill of the cutter to kindle the fire hidden within the diamond. Although the choice of your diamond depends on personal feelings and taste, there are objective quality criteria.

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THE 4 Cs

Cut, Clarity, Colour und Carat

Four criteria determine the value of a diamond and thus also its price: cut, clarity, colour and carat (weight). No diamond is like any other, even if they appear identical to the naked eye. You have to know the 4 Cs and their combination possibilities to understand why two gemstones of the same size can have very different prices.


The highest quality feature of the 4 Cs: the diamond´s cut. The colour, purity and size of the diamond are predetermined. But it´s not until the diamond is cut in the right proportions that it achieves its full brilliance. The most important thing in this process is the know-how and experience of the cutter, who can create a masterpiece out of a rough diamond.

The type of cut depends on the natural raw shape of the diamond. However, only diamonds that are round and have at least 57 facets deserve the label „brilliant“.

A good cut optimally brings out the fire of a diamond: The light is reflected from one facet to the other and shines back through the surface of the stone.

Throughout their history, diamonds have come in many exciting and alluring forms. The most popular cut is undoubtedly „the brilliant“. The variety of shapes seems unlimited and imaginative and no cut shape is more beautiful than the other, but each a work of art in itself.

Odoo • Text und Bild
Odoo • Bild und Text

Only the well-proportioned cut gives the diamond its unmistakable glow. The cut is the criterion that humans can directly influence – all others have been predetermined by nature for each stone. A good cut reflects the proverbial fire of a diamond through correct proportions and the arrangement of its facets (the surfaces that reflect light at certain angles).


The purity or clarity is another quality criterion of the 4 Cs for diamonds. Like no other gemstone, the diamond can achieve a unique brilliance. It is considered absolutely pure if it does not show any inclusions. Classic inclusions are foreign crystals such as garnets, spinels or peridots - even another diamond can be present as an inclusion. Too many or coarse inclusions can prevent incoming light from being fully reflected.

In addition to inclusions, stress cracks and fracture cracks as well as various growth features are also considered purity criteria in diamond ratings. A diamond only receives the rating „flawless“ (if = internally flawless) when even experts can no longer make out internal features such as inclusions, at ten times the magnification. Flawless diamonds (if = internally flawless) are extremely rare.

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Odoo • Bild und Text


The third of the 4 Cs for diamonds stands for colour. Diamond valuation experts state the colour of the stones with letters from D to Z. D stands for the highest colour level and Z for the lowest. In the specialist trade, diamonds from D to H are referred to as “white diamonds”. From colour level I, the stones have an increasingly yellowish tone.



Although the diamond is mostly found in its transparent form, it is extremely rare in flawless white. Unpolished diamonds are also yellow in colour. So-called “fancy diamonds” or coloured diamonds are just as rare as bright white diamonds. They have tinges outside of the colours D to Z and come in all colours, red, orange, yellow, green, blue, violet, brown, grey and black.


The weight and therefore the size of a diamond is measured in carats. Carat comes from ceratonia, the seed of the carob tree, which was used in former times to weigh precious stones because of its uniformity. The weight is usually specified with two decimal places. The abbreviation for carat is "ct".

1 carat is equal to 0.2 grams. Two diamonds with the same carat weight can still differ greatly in their price - because their value also depends on their cut, colour and purity.

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Odoo • Bild und Text

The  5th C


Diamonds that are suitable as material assets must have a professional and internationally recognised appraisal (certificate).

This documents both the quality parameters of the stone and information about its identity and/or authenticity. Based on its characteristics, the "4 Cs" (Carat, Colour, Cut, Clarity), the value of the diamond can be determined precisely. Therefore, the certificate belonging to the stone can also be referred to as the “fifth C” because it serves as an objective guideline in the diamond trade.