GIA Diamond Evaluation Criteria

The GIA Gemological Institute of America pioneered the diamond grading system, called the 4C standard, which unified the global grading criteria for diamond quality and became the recognized identification standard in the industry today ; it also allows consumers to accurately understand the quality and characteristics of the diamonds they choose, and its significance. major. The 4C standards include: Carat weight, Clarity , Color, and Cut . Today, the 4C standards have been widely used in diamond quality certification processes around the world.

1.Carat weight•Carat is the unit of weight of diamond.

•A tool for measuring diamond weight, carob seed → mechanical chain scale → electronic carat scale. •One carat = 100 points = 0.2 grams •The weight of a diamond is recorded to the second decimal place below one carat, and the third decimal place and below are not counted, unless the third decimal place is 0.009, then it can be rounded up to 0.01. •Diamond sieves usually use a measuring tape for each disc as the approximate size, and the diameter of each small hole represents each weight of diamond.

2. Clarity • The classification of clarity grades is based on observation under ten times magnification.

•The clarity of a diamond is its purity and transparency. Clarity characteristics are called inclusions on the inside and gaps on the outside. Factors such as the size, number, location, nature, and conspicuity of features determine the clarity grade. •Although most diamonds contain very fine inclusions, these inclusions do not affect the beauty of the diamond itself. However, the fewer and smaller the inclusions, the greater the impact on the penetration of light into the diamond. The lower it is, the more beautiful the diamond will shine.
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English name

Chinese name





Flawless inside and out


Internally Flawless

internally flawless

Although there are no defects internally, there are very minor defects externally.


Very Very Slightly Included 1

Very Slightly Contains Level 1

Very slight flaws, difficult to detect


Very Very Slightly Included 2

Very Slightly Contains Level 2

Very slight flaws, difficult to detect


Very Slightly Included 1

Slightly Contains Level 1

Tiny flaws, difficult to observe


Very Slightly Included 2

Slightly Contains Level 2

Tiny flaws, difficult to observe


Slightly Included 1

Micro inclusion level 1

Obvious flaws are easily noticeable but cannot be seen with the naked eye


Slightly Included 2

Micro inclusion level 2

Obvious flaws are easily noticeable but cannot be seen with the naked eye


Included 1

Contains level one

Obvious flaws, visible to the naked eye


Included 2

Contains secondary

Large and many defects are visible to the naked eye and affect its brightness


Included 3

Contains three levels

Serious flaws, which have reduced the transparency and brilliance of the diamond, the boundary of industrial diamonds

WILLS JEWELLERY diamond jewelry series

WILLS JEWELLERY uses the most stringent requirements to select diamonds with color F/G or above and clarity SI-VS or above, and set them in its own jewelry designs to create sparkling and dazzling diamond jewelry. Our store guarantees that every diamond is natural and non-artificial, giving you the greatest confidence.

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3.Color color·Diamond color grading

According to GIA's color grade table, there are 23 grades from D to Z in English letters, ranging from the completely colorless and extremely rare D to the yellowish-brown Z, with different shades of color. •D. E. F. grade belongs to the colorless range, G. H. I belongs to the nearly colorless range, J. K. L is slightly light yellow, and M. N and below are light yellow. •In addition to the high value of colorless diamonds, the value of colored diamonds is also very high.

4. Cut • Cut is the shape and style of a diamond

Diamond cutting shapes are usually divided into two categories: round diamonds and fancy diamonds. The most common diamond cut is the brilliant round diamond. Fancy diamonds are also called fancy cuts, which mainly include: cushion-shaped, emerald-shaped, heart-shaped, drop-shaped, princess-shaped, marquise-shaped, oval, and minefield. en form etc.
•Nature gives each rough stone different characteristics. The quality of the finished product is closely related to the original stone and cannot be changed by manpower. However, through the cutting skills of the cutter, its most beautiful side can be brought out and Create maximum value.
•The factor that makes a diamond so outstanding depends entirely on its cutting. If its cutting proportions are good, the diamond can exert its maximum optical properties, showing perfect white light, sparkle, and fire. Fluorescence reaction Fluorescence reaction refers to the reaction color light that occurs when a diamond is exposed to ultraviolet light. Fluorescence reaction has two main effects on diamonds: 1. Affects fire--the stronger the fluorescence, the more opaque the diamond will look. 2. Change the color - diamonds with the same color H, diamonds with moderate fluorescence look whiter; on the diamond appraisal certificate, the fluorescence reaction is the test item Medium (moderate) fluorescence and above, which has an impact on the price of the diamond. will have an impact.


WILLS JEWELLERY What's so special about wearing diamonds? The answer is to deliberately cut the diamonds into pairs during the polishing process, regardless of the cost. Many so-called set diamonds in the market are just two diamonds with similar shapes put together; WILLS's set diamonds allow craftsmen to simultaneously polish and cut two unpolished rough stone embryos according to the selected ideal shape. For matching sets, it is important to cut the two diamonds into exactly the same shape at all costs, so that they can be called matching diamonds.

WILLS JEWELLERY stocks white and colored diamonds of different shapes, ranging from 30 carats to more than 5 carats. All diamonds are certified by GIA. If you need a quote for GIA diamonds, please fill in the information form below or make a Whatsapp inquiry. Our store will get back to you as soon as possible.

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