Diamond quality factors-Part-1

One fact that almost everyone knows is that not all diamonds are "born" equal. In fact, every diamond is unique. Diamonds come in various sizes, shapes, colors, and have different internal characteristics.

All polished diamonds are very precious. This value is a combination of many factors. Rarity is one of the factors. Diamonds with certain characteristics are more rare than other ordinary diamonds, and certainly more valuable.

Jewelry professionals use a systematic approach to evaluate and discuss these factors. Otherwise, the two diamonds cannot be compared with each other. Also, we cannot evaluate and discuss the quality of individual diamonds. Professionals use the diamond grading system created by GIA in the 1950s, which establishes four important factors for describing and classifying diamonds: clarity, color, cut, and carat weight.

People call it 4C. These factors are called 4Cs and are used to describe the quality of polished diamonds. The value of polished diamonds depends on the combination of 4Cs.

The value of a diamond is often determined by the rarity of one or more factors in the 4C. Colorless diamonds are very scarce-most diamonds have a faint yellow or brown color. Therefore, in the color grading table, the grade of colorless diamonds is higher than that of light yellow diamonds. Value and rarity are closely related: in this case, colorless diamonds are rarer and more valuable than light yellow diamonds. The rarity of clarity, cut and carat weight and diamond value follow the same relationship.

4C describes the quality of diamonds, and the value of diamonds depends on these qualities. The terms that people use when discussing 4Cs have become the international language used by jewelry professionals to describe and evaluate diamonds.

Nowadays, the diamond industry’s description of each “C” in the “4C” is very precise, and it is more precise than almost any other consumer product’s quality description. Their history is very long. Three of these factors (color, clarity and carat weight) were the basis of India's first diamond grading system as early as 2000 years ago.

colour

The nuance of color can greatly affect the value of a diamond. Two diamonds have the same clarity, weight, and cut diamonds, and only the difference in color can make their value very different. Even very subtle differences can make a dramatic difference in the value of diamonds.

Diamonds come in many colors. The general color range of diamonds actually refers to colorless to light yellow or light brown. Colorless diamonds in this color range are the rarest, so they are also the most precious. Within the general color range, other diamonds also have corresponding grading and pricing standards.

Examples of GIA diamond color grade ranges

These diamonds (E, K, and Z) represent the color of the diamond at the top, middle, and bottom of the GIA color scale. -© GIA & Tino Hammid

In the GIA laboratory, diamonds will be compared with round brilliant diamonds called colorimetric stones under strictly controlled conditions to grade the color of the diamond.

Some diamonds emit visible light when exposed to ultraviolet light (UV). Although it cannot be seen with the naked eye, ultraviolet light is everywhere. Sunlight contains ultraviolet rays. Fluorescent lamps can also emit ultraviolet light. Under the right conditions, you can see fluorescence in approximately 35% of gem-quality diamonds.

Blue is the most common fluorescent color in gem-quality diamonds. In a few cases, the fluorescence can be white, yellow, orange, or many other colors.

The strong blue fluorescence can make a light yellow diamond closer to colorless under sunlight. Blue and yellow are complementary colors and can often cancel each other, so blue fluorescence can mask the yellow color of diamonds. If the fluorescence is too strong, it will give the diamond a cloudy or "oily" appearance, thereby reducing its value.