Information about diamonds (Diamond info)
The value of a diamond is influenced by cut, weight, color and clarity. These components are called 4C, which comes from their English names: cut (grinding), Carat (weight), color (color) and clarity (purity). Fluorescence can also affect the value of a diamond.
Most of the diamonds belong to the Cape series, which includes diamonds ranging in color from colorless to yellow. When talking about this type of diamond, a colorless diamond is rarer than a diamond with a hint of yellow. Because of this, colorless diamonds are more valuable than yellowish diamonds. Likewise, heavier and cleaner diamonds are rarer, and therefore more valuable, than small and impure diamonds. Thus, it can be said that purity, color and weight are the rarity factors of a diamond. Grinding, on the other hand, is a quality factor of a diamond.
The diamonds used in our Black Label series jewelry have purity class VS. Our Red Label series jewelry uses diamonds of the SI purity class. In terms of color class, the diamonds we use are always at least H (Wesselton).
Grinding
Cut is the most important of the four factors that affect the value of a diamond, as it affects the beauty of the stone the most. In a well-cut diamond, the brilliance, fire, sparkle and shine of the stone come out in the best possible way.
When the diamond has been cut to the right dimensions, the light coming into it is reflected back through the largest chamfer on the top of the stone, or tableau. In this case, the stone looks bright and lively. When the lower part of the stone is too deep or shallow in relation to the diameter, the brilliance of the stone decreases.
Brilliant cut is the most common form of diamond cut. The figure below shows the grinding ratios of a brilliant-cut diamond. Grinding ratios are given as reference numbers in relation to the diameter of the stone, i.e. the size of the brilliant.
A few other common forms of diamond grinding are shown below.
- princess sanding
- Marquise i.e. navette or awning sanding
- radiant grinding
- Emerald or emerald grinding
- asscher grinding
- heart i.e. a brilliant cut in the shape of a heart
- pear i.e. drop-shaped brilliant
- cushion i.e. cushion sanding
- oval brilliant
Clarity
The clarity of a diamond describes the number, location and size of the external or internal marks in the stone. The purity classification is done with a tenfold magnification. External signs can be, for example, small scratches caused by sanding or extra bevels. "Impurities" inside the stone are called inclusions. For example, foreign minerals, block faults and growth zones inside a diamond are inclusions.
The following table shows the diamond purity classes with their descriptions.
| Cleanliness class | Abbreviation | Description of purity class |
| Flawless | FL | The stone is completely clean. No inclusions or external marks. |
| Internally Flawless | IF | There are no inclusions in the stone, but there are very few external signs. |
| Very, Very Slightly Included 1 | VVS1 | There are very small inclusions in the stone that are very difficult to notice. |
| Very, Very Slightly Included 2 | VVS2 | The stone has very small, hard-to-detect inclusions that may be in the area of the board. |
| Very Slightly Included 1 | VS1 | There are small, colorless, hard-to-detect inclusions in the stone. |
| Very Slightly Included 2 | VS2 | The stone has small, rather hard-to-detect inclusions. Closures can be dark and located in the board area. |
| Slightly Included 1 | SI1 | There are inclusions in the stone that can be seen quite easily with 10x magnification. |
| Slightly Included 2 | SI2 | There are inclusions in the stone that can be easily seen with 10x magnification. |
| Included 1 | I1 | There are inclusions in the stone that are immediately visible with 10x magnification, which are also visible to the naked eye. |
| Included 2 | I2 | The stone has inclusions visible to the naked eye, which affect its beauty and durability. |
| Included 3 | I3 | The stone has very large inclusions visible to the naked eye, which significantly affect the beauty and durability of the stone. |
Color
Cape series diamonds are classified according to their degree of colorlessness. In Finland, traditional designations (Northern Diamond Nomenclature, or PTN) have been generally used for different color categories, but nowadays it is recommended to use the color scale developed by GIA. The attached table summarizes the GIA color scale and the PTN color classes that correspond to its color classes.
| GIA | PT | Description |
| D | River | The rarest colorless |
| E | ||
| F | Top Wesselton | Rare colorless |
| G | ||
| B | Wesselton | Colorless |
| I | Top Crystal | A little nuanced |
| J | Crystal | |
| Q | Top Cape | Scented |
| L | ||
| M | Cape | Slightly yellowish |
| OF | ||
| O | Light Yellow | Yellowish |
| P | ||
| Q | ||
| R | ||
| S | Yellow | Yellow |
| T | ||
| U | ||
| V | ||
| X | ||
| Y | ||
| Z | ||
| Fancy |
Colored diamonds
Colored diamonds (fancy colors) are rare and therefore often very valuable. Because of this, several artificial processing methods have been developed to create colored diamonds. Colored diamonds are also produced synthetically in laboratories. Diamonds can be found in nature in brown, yellow, green, black, blue and pink. Only a few red diamonds have been found.
The color classification of colored diamonds differs from the classification of colorless and almost colorless diamonds. In the color classification of colored diamonds, color intensity and purity are evaluated.
Weight
The weight of a diamond is indicated in carats (eng. carat, abbreviation ct). One carat weighs 0.2 grams.
Since the carat number only indicates the weight of the diamond, the diameter and height of diamonds of the same weight may differ from each other. Below are indicative diameters for different sizes of round brilliants.
| Weight (ct) | 0.25 | 0.50 | 0.75 | 1.00 | 1.50 | 2.00 | 2.50 |
| Diameter (mm) | 4.1 | 5.15 | 5.9 | 6.5 | 7.45 | 8.2 | 8.8 |
Fluorescence
Fluorescence refers to the phenomenon where a diamond "glows" e.g. blue when it is illuminated with ultraviolet light. The fluorescence color of a diamond can be blue, green, orange or yellow. However, not all diamonds fluoresce.
Because sunlight contains ultraviolet radiation, strong fluorescence can cause a diamond to appear cloudy in sunlight. In this case, the fluorescence affects the value of the diamond in a lowering way. However, yellowing stones may appear more colorless due to the effect of blue fluorescence, in which case the fluorescence increases the price of these stones.
Diamond research reports
Diamonds weighing more than 0.30 ct used in our jewelry are accompanied by a GIA (Gemological Institute of America) research report. There are other reputable diamond labs, but the GIA test reports are generally the most highly regarded. This is partly because the GIA has developed the color and purity grading scales commonly used in the industry today.
The stones we use over 0.30 ct have a color of at least H (PTN Wesselton) and a purity of at least VS1. In addition, we only use stones that have received an excellent rating in the research report for grinding, symmetry and polishing quality.