How to choose the right diamond

The main criteria for choosing a diamond

If you have decided to invest in diamonds, you need to know the criteria used to select diamonds. The evaluation is carried out by internationally recognised gemological laboratories.

These criteria determine the value and quality of a diamond, they are 4 and are referred to as the 4Cs :

clarity -CLARITY, color - COLOR, cut - CUT, weight - CARAT.

When selecting a diamond, you need to be clear whether the diamond will be part of a piece of jewelry that will please your eye and also be an investment or if you choose to buy an investment diamond that is never part of the jewelry.

The criteria for evaluating a diamond

Clarity of the diamond - CLARITY

The clarity of a diamond refers to the degree of internal defects. These can be crystals of foreign material, uncrystallized carbon, or structural flaws such as small cracks that can cause a whitish tint to the diamond. The most valuable diamonds are completely clean and ideally crystallized. However, such diamonds are rarely found. Only about 20 percent of mined diamonds are of sufficient clarity to be used in jewellery. The other 80 percent are used industrially as cutting tools or abrasives. While inclusions reduce the price of a diamond, they also serve a diagnostic purpose. They indicate that the stone is genuine (of natural origin). External characteristics such as scratches etc. are not included in the clarity assessment.

Inclusions can be found in almost all rough diamonds, the most common being:

• crystalline inclusions - crystals of other minerals or other diamonds that were present when the diamond was formed
• cracks, fissures, fractures
• clouds

The clarity of the diamond is examined by an experienced expert with a special 10x magnifying aplanatic achromatic loupe, in normal light. The location, size and type of inclusions detected are always precisely stated in the diamond certificate. A flawless diamond is considered to be one that has no visible blemish even at 10x magnification. The clarity of the diamond can be additionally improved, e.g. by laser treatment, but the intervention must be clearly described in the certificate, e.g. "laser drilled". The clarity classification then corresponds to the clarity of the stone after treatment.

Diamond colour - COLOR

The colour of diamonds varies greatly in nature. If the diamond was created under perfect conditions, it is colourless. In nature we can encounter a wide range of colours. From colourless diamonds, to slightly yellowish ones, to orange, pink, purple, blue or even extremely rare red stones. Common coloration - most stones range in color tones from slightly yellowish to brownish yellow. This coloration reduces the price of the stone. Yellowish diamonds are classified as "Cape" or "Cape Series" and are less expensive. The colour of a diamond is judged according to the GIA (Gemological Institute of America) colour scale, which divides diamonds by colour using letters of the alphabet from D to Z. The letter D denotes completely colorless diamonds (pure white+) and most colored by the letter Z see the GIA color scale chart below.

The more colourless the diamond, the more expensive it is. An exception are so-called fancy diamonds, natural coloured diamonds. These are not covered by the GIA scale and can surpass even perfectly colourless diamonds in price. The colour is assessed using a comparative set of stones, called master stones, under a lamp that imitates daylight. An electronic colorimeter is also used to determine the colour of the stone. Although technical devices are developing rapidly, no commercially available colorimeter has yet replaced the human eye.

Diamond cutting - CUT

Diamond cutting is a jewellery making activity in which rough diamonds are cut to create gemstones suitable for jewellery. A rough diamond only gains its beauty after it has been cut. For larger and more expensive stones, cutting is done by hand, while smaller stones are now mostly cut by machine.

The quality of diamond cuts is assessed in terms of proportions, surface finish and symmetry.

According to the international scale, there are five grades of cut quality:

Excellent/Ideal cut, Very good, Good, Fair and worst Poor.

The following are also evaluated for the cut:

• the amount of reflected white light - brilliance
• the decomposition of the light coming from the cut stone-fire
• the degree of colour play when the stone or head moves - sparkle

Diamond cuts

• Brilliant-round cut, the best known and most widely used cut with 57 facets that are cut to precise proportions.
• Princess-This is a quadrilateral cut with sharp corners, sometimes also triangular.
• Emerald-emerald cut, is typical of its rectangular shape, shortened corners and wide surface, which when viewed from above resembles a staircase.
• Asscher-famous not only for its exceptional brilliance, but also for the typical and beautiful optical illusion known as the "hall of mirrors". very often this shape is confused with the square emerald shape, whose shape is almost identical and disagreements often reign over their exact differences.
• Pear-shaped (teardrop-shaped)
• Radiant-square shape with distinctive 'clipped' corners.
• Oval-rounded elongated shape.
• Cushion-Rectangular or square shape with typical rounded corners, resembling a cushion, hence its name 'cushion'.
• Heart-shape is most often composed of 56 to 58 facets.
• Marquise-The shape of a marquise cut gemstone resembles the hull of a ship in its double-tipped design.
• Triangle-The shape of a triangle.
• Baguette-rim.

Weight of diamond - CARAT

• The weight of a diamond is given in carats, abbreviated as ct. It is a different carat than gold, which is a unit of purity and has the abbreviation ct.
• A metric carat (Carat) is defined as 0.2 g and is denoted by ct.
• A diamond weighing 1 gram is therefore 5 ct or 1 ct = 200mg=1/5 gram.
• Diamonds in commonly sold jewellery are usually in hundredths, tenths or even units of carats.

Weight and price

The price of a diamond does not increase in proportion to its weight. In fact, large diamonds are rare and thus more valuable. A 2 carat diamond is therefore more expensive than two 1 carat diamonds with otherwise the same characteristics. The largest diamonds found are thousands of carats.