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All you need to know about diamonds!

Diamond earrings, Diamond House Jewellery – Photo ©Bérengère Treussard

Diamond earrings, Diamond House Jewellery – Photo ©Bérengère Treussard

« Help ! My man wants to buy me a diamond but I don’t know how to choose! » I have heard this too often!  Keep cool! It’s not so complicated: follow a few basic rules and trust your eye and your heart, they are your best allies!

The basic “4 C” rule makes it easy:

The diamond has four evaluation criteria called the 4 C: Carat, Clarity, Colour, Cut.
Let me explain :

Carat: The weight of a diamond is expressed in carat and a carat is equal to 0.20 gram. The carat is divided into 100 points. For example a diamond of 0.50 carat is equal to a diamond of 50 points. Carat is also the unit of weight measurement of precious stones and fine stones.

You may be surprised by the price difference between a diamond of 0.99 carat and one of 1 carat or more, the same goes for a 2 carat diamond. I recommend you to choose a diamond a little below the desired caratage, nobody will know that your rock is 1,99 ct instead of 2. It is not visible to the human eye!

Clarity: The purity of a diamond is very important to determine its price. It is very rare to have diamonds with little or no inclusions. International standards have established that a diamond is said to be pure from the moment an expert’s eye detects no defect using X10 magnifying glasses. A purity scale has been established to classify the diamond according to its degree of purity:

– Pure: Flawless / Internally flawless
– Very very small inclusions: V VS1 or V VS2
– Very small inclusions: VS1 VS2
– Small inclusions: SI1, SI2 or SI3
– Imperfect or Piqué: I1, I2 , I3 or P1, P2, P3

You got it, simply avoid visible inclusions and better also avoid P diamonds. However, do not worry if it is not Flawless! Except if your beloved one is a connoisseur and insists absolutely to offer you a D Flawless… in that case, be happy!

Colour: Colour has a true impact on the diamond’s value. The colour scale runs from D to L. You must know that to determine the colour, the diamond is observed from the culet, under a lamp specially dedicated to this use. If the lighting were different, the perception of its colour would also be. The scale starts at D for a perfectly colourless diamond. The colours from E to I are white or near-colourless. After the letter I, the shade of yellow increases gradually until the letter L. If the diamond exceeds the letter L it is increasingly yellow until Z. Note that it is very difficult for an untrained eye to perceive the shades of yellow in a diamond. Diamonds classified from M to Z have a more pronounced colouring and are defined as coloured. Beyond the Z classification, diamonds are called “fancies”. They form a distinct, very valuable, category.

My advice is to choose a diamond that is between the colour D and I. For small diamonds it is very difficult to make a difference and the good value for money is often a H, especially for a pendant or earrings. For an engagement ring, it all depends on the size, proportion and symmetry.

Cut: The cut refers to the balance of proportion of a diamond. A very well cut diamond allows the maximum amount of light to enter through its top and to be reflected and dispersed back through its top (the « table »). The cut enhances the diamond’s brilliance, scintillation and dispersion, also called « fire ».

Main types of cut.

Main types of cut.
Round ; oval ; marquise ; pear ; cushion ; heart ; emerald ; princess ; radiant ; baguette.

Proportion and symmetry are essential in the choice of a diamond, noted as Excellent, Very Good, Good, Fair, these criteria are additional to the cut. They allow the stone to have an optimal shine, and this will make the stone look bigger because there will be no loss of light reflection.

Diamonds have not always been cut the same way. Currently, the most common cuts are the round cut (57 or 58 facets) and the ancient or half-cut (1930) that you will find on vintage jewellery. The rose cut is coming back and many jewellers use it in their creations to give a vintage and ancient aspect which I am quite fond of myself.

Did you know that the marquise cut is a homage of Louis XIV to his mistress the Marquise de Pompadour? The story says he wished to make immortal the memory of her lips…

Marquise cut diamond – Diamond House Jewellery

Marquise cut diamond – Diamond House Jewellery


IN ALL CASES, DON’T PANIC, all these criteria are grouped in a certificate when the stone is important enough, which is a kind of diamond ID. The widespread use of certificates by laboratories started in the late 1970s. Previously, less than 1% of diamonds were certified. This certificate makes it possible to check all the characteristics of a diamond in particular the 4Cs, the specifics of possible inclusions and, of course, if it is natural. Only natural diamonds can be certified.

Each diamond is unique, even though some may have the same colour and purity, there will always be differences. Only a few laboratories are known worldwide: the GEM (Gemmological Institute of America), the HRD (Hoge Raad voor Diamant) the IGI  (International Gemological Institute), but there are others.

Beyond all these technical terms and criteria, there is your feeling for the stone. You can have two identical stones yet one will attract you more than the other… As for love, follow your heart.

A diamond to win, round cut, 0,25 ct - Diamond House Jewellery - Photo © Bérengère Treussard

A diamond to win, round cut, 0,25 ct – Diamond House Jewellery – Photo © Bérengère Treussard

I am proud to announce that Diamond House Jewellery has chosen Like a b to make you win a 0.25 carat, purity VS, colour G diamond.

Get a chance to win, it’s easy:

1. go to my Instagram,
2. choose your fav’ photo among those with the hashtag #lovediamondhousejewellery,
3. repost on your Instagram (must be public) with the same hashtag,
4. follow Diamond House Jewellery’s Instagram

So what are you waiting for?

RESULT on INSTAGRAM on December 16, 2015. On my birthday!

Good Luck!

Thank you to Sarah B from AFG (French Association of Gemmology) for the help and advice.

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