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There are four main dimensions to measure the quality of a diamond, namely, weight (carat), clarity, color (color) and cutting (cutting), which is also commonly known as "4C standard". Founded by GIA (Gemological Society of America), this standard is the most mainstream diamond evaluation standard in the world, including China.

Diamonds are appraised by internationally recognized gem experts, and independent opinions are issued by third parties. Determine the price of diamonds based on 4C standard.

colour

Colorless is the best, and the darker the tone, the worse the quality. In the classification of colorless diamonds, the top color is D color, which is arranged down to Z in turn. Here, only the color scales from D to J are mentioned. D-F is a colorless color scale, and G-J is close to a colorless color scale. Starting from K, there is basically no collection significance, and the ring holders below K color are also very beautiful. Because diamonds will gradually turn yellow from K, when choosing diamonds, choose the color above H. I-J grade also belongs to the category of near colorless, but a trace of yellowish diamonds with yellow, green, blue, brown, pink, orange, red, black and purple are precious and expensive among diamonds. Red diamonds are the most expensive.

Different countries and regions adopt different color grading systems. American Gemological Institute is divided into 23 grades, which are represented by English letters D-Z respectively. The most commonly used one is 1 1 level d-n. The color grading system in Europe is represented by CIBJO. The newly formulated Chinese national standard 1996 integrates GIA and CIBJO, divides colors into 12 grades, and uses D-N and.

From the D level down, the price also becomes lower. The price difference of each color scale is generally 10%-45%, and the price difference between high color scales is higher than that between low color scales.

Diamond color grade

D 100 extremely white

E 99

F 98 youbai

Group of 97

H 96 white

I 95 yellow and white (brown, gray)

J 94

K 93 light yellow (brown, gray) white

L 92

M 9 1 light yellow (brown, gray)

N 90

& ltn & lt90 Yellow (Brown, Gray)

clean

Diamond-Gold Celebration

Diamond-Gold Celebration

Clarity classification is based on the position, size and quantity of inclusions. From high to low, it can be divided into FL, IF, VVS 1, VVS 2, VS 1, VS 2, Si 1, Si2, Si3, P 1, P2, P3. Observe the diamond carefully under a ten-fold microscope.

In ...

FL-"perfect", perfect. Under the magnifying glass of ten times, there are no flaws inside and outside.

If-"immanent", immanent. Under the magnifying glass of ten times, only the surface has slight flower marks.

Vvs 1, vvs2-"very very thin", very very small. There are defects that are difficult to see under a magnifying glass of ten times. The definition of VVS 1 is higher than that of VVS2.

VS 1 and vs 2-"very thin", very small. Defects can be seen under a magnifying glass of ten times, but it is difficult for the naked eye to recognize them. The definition of VS 1 is higher than that of VS2.

Si 1 and si2- "slight inclusions", small flaws, which may be visible to the naked eye.

I 1, I2, i3-"Imperfect" is flawed and visible to the naked eye.

According to Chinese standards, LC to P can be subdivided into 10 grades, and grades below P are generally not used as gem diamonds. Diamonds are divided into five grades: excellent, very good, good, better and average.

Diamond clarity is divided into 10 grade, but pay attention to "small grade". For example, at the VS level, VS 1 and VS2 are different. When purchasing finished diamond ornaments, the state allows diamond ornaments below 0.47 carat to be classified into different grades. So you bought diamonds smaller than 0.47 carat, and carefully spent VS 1 to buy VS2 diamonds.

carat

D grade diamond

D grade diamond

Under the same conditions as the other three C's, the price of a diamond is directly proportional to the square of its weight, and the greater the weight, the higher its value. The weight of diamonds is measured in carats. 1 carat (carat) = 0.2g (gram). Divide one carat into 100 parts, with one point for each part. The price tag in the mall says 0.3ct, and 0.4ct stands for 30 minutes and 40 minutes. The weight is also graded, 0.30ct-0.39ct, 0.40ct-0.49ct, 0.50ct-0.69ct, 0.70-0.89ct, 0.90-. 1.50-2.00ct (each level is separated by a comma, not the first level. Even if it is one point short, the price will vary a lot, which is why it is difficult to buy such things as 0.48~0.49, 0.68~0.69, 0.88~0.89 ...). On the diamond certificate, the diamond's

Diamonds are rare and generally not large. Generally speaking, diamonds with a weight of 0. 1-0.24 carats are called small diamonds, which are mainly used for setting clothes or other gem ornaments. Diamonds with a weight of 0.25- 1 carat are mainly used as the main body of diamond jewelry, and the price of rings can also be accepted by the public; Diamonds larger than 1 carat can be used for investment, which has a certain ability to maintain and increase value.

Diamonds are priced by grades, such as 18-22, 20 grades, 28-39, 30 grades and so on. (Please consult at the time of purchase for details). The price difference of a grade sometimes reaches 1000 yuan or more. If you learn to choose a reasonable weight, you can save a lot of money.

incision

Star of Africa Ⅰ

Star of Africa Ⅰ

Cutting refers to the geometric shape and arrangement of various valve faces of finished bare diamonds. Cutting is divided into three categories: cutting ratio, polishing and decoration. Each item has five grades, from high to low, excellent, very good, good, average and poor. Generally, diamonds are cut by standard round diamonds. Top-cut stone can achieve the most perfect ratio of light reflection, that is, three-EX (excellent) cut, but the price of this cut is a little more expensive, because its yield is relatively low, about 5% higher than that of non-three-EX cut, but the color of stone cut with three-EX is absolutely the most beautiful.

Other common cutting forms are round emerald, oval, pear-shaped, princess square, pillow-shaped, heart-shaped, eight hearts and eight arrows-Cupid cutting and so on.

Every country has different cutting standards. China's national inspection divides diamond cutting into three grades: excellent, good and average.