Color grading of diamonds
The price of diamonds is determined by 4C parameters, and the more colorless the color, the more valuable it is. Because the color of diamond is equivalent to a high-quality filter, its function is to reduce the escape of reflected light. The whiter the color of the diamond, the more intense the color of the diamond flashes. Similarly, the rarer colorless diamonds are compared with yellow, and according to the different degrees of gem color from light to dark, the grades are divided into D, E, F, G, H, I-J, K-L, M, N-O, P-R and S-Z. Most gem-grade diamonds range in color from colorless to light yellow.
Grade d: completely colorless. The highest color level is extremely rare.
Class e: colorless. Only gem experts can detect trace colors. This is a very rare diamond.
Class f: colorless. A small amount of color can only be detected by jewelry experts, but it is still considered colorless. It belongs to high quality diamonds.
G-H grade: almost colorless. Compared with higher grade diamonds, it has a slight color. But diamonds of this color still have high value.
I-J grade: almost colorless. A slight color can be detected. The value is higher.
K-M grade: dark color, poor fire color, wedding diamond ring net is not provided, and customers are advised not to use it.
N-Z grade: dark color, poor fire color, no wedding diamond ring net, customers are advised not to use it.
Diamond clarity classification
Inclusions in diamonds refer to impurities, including clouds and cracks. The less inclusions, the higher the clarity grade, the rarer the diamond and the higher its value. Observe the diamond with the naked eye, if there is no flaw. Clarity grade SI 1 and above usually belong to this kind of diamond. The following are different levels of clarity.
FL: Flawless-when viewed by professionals under the magnification of 10, there are no flaws inside and outside, which is the rarest and most precious among all cleanliness grades.
If: flawless interior-professionals observe under the magnification of 10, there are no flaws inside, but there are tiny flaws on the diamond surface.
VVS 1: Very tiny flaw1-At the magnification of 10, professionals only observed a tiny flaw.
Vvs 2:2: Very tiny defects-professionals observed individual tiny defects under the magnification of 10 times.
VS 1: micro-defect 1 level-10 times magnification, you can see a single micro-defect.
VS2: Minor defect level 2- 10 times magnification, you can see several minor defects.
SI 1: small defects 1 level-10 times magnification, obvious defects are easy to observe.
SI2: Small defect level is 2- 10 times magnification, and several obvious defects can be easily observed.
Eight hearts and eight arrows is one of the technical terms of diamonds. Also known as "Cupid" cutting. Eight hearts and eight arrows are perfectly symmetrical, and the precise and flawless cutting is amazing.
The most common forms on the market are: 1 desktop, 8 kite facets, 8 star facets, 16 waist facet, 16 waist facet, 8 main facets at the bottom, and a sharp bottom that may or may not be available, totaling 57 or 58 facets. The following figure clearly shows the specific position of the above surface of the diamond: well, you can clearly know it when you see this picture. Someone always asks why there are 57 faces and 58 faces. It's actually quite simple. It is located at the cusp of a diamond-the bottom tip. Generally speaking, diamonds smaller than 5 carats do not have a bottom tip, so the position of the bottom tip of the backing on the certificate is not or very small, and so on. , that is, the bottom tip is not or too small to be ignored, that is, 57 faces. However, in order to protect diamonds from damage, the bottom tip of Culet is generally polished, so there is an extra face, which is 58 faces. Many people tend to think that the more diamonds, the better. Actually, it's not. There are many kinds of diamonds, especially irregular diamonds, which can extend to many sides. Not all kinds of diamonds have more faces, the better. As a round drill, the standard bright cutting (57-58 faces) is also a classic lathe, which is a very classic and perfect cutting method. The values of the above 57 faces directly affect the quality of diamond cutting, so we call the diamond cutting with the most standard proportion within a certain numerical range "ideal cutting", that is, "ideal cutting", and diamonds can shine the most perfect light under such numerical standards! Therefore, this kind of diamond is the most worth collecting and investing, and it is also the most expensive under the same conditions as other 3C.
Diamond cutting ratio
Ratio refers to the percentage of other parts relative to the average diameter of the waist. Proportion is the most important factor to determine the quality of diamond cutting. The proportion is just right, and the diamonds are dazzling. On the contrary, diamonds are eclipsed. The ratio includes the ratio of the relative average diameter of each part of the diamond, mainly including the following eight ratios:
Table width ratio: the percentage of crown surface width to waist average diameter;
Crown height ratio: the percentage of crown height relative to the average waist circumference;
Waist thickness ratio: the percentage of waist thickness relative to the average waist diameter;
Pavilion depth ratio: the percentage of pavilion depth relative to the average waist diameter;
Bottom tip ratio: the percentage of the maximum diameter of the bottom tip to the average diameter of the waist;
Full depth ratio: the percentage of the vertical distance from the crown top to the bottom tip relative to the average waist diameter;
Crown angle ratio: the angle between the main facet of the crown and the horizontal plane where the waist is located;
Pavilion angle ratio: the angle between the main facet of the pavilion and the horizontal plane where the waist is located.
The influence of diamond proportion on diamond cutting: the size of the table directly affects the brightness and fire color of diamonds. If the table is too big, the brightness will be higher and the fire color will be lower. The mesa is too small and the brightness is too small, but the fire color will increase. When the table width ratio is 53%, the fire color is the most perfect, but this kind of cutting and grinding is often at the expense of diamond weight loss, so cutting and grinding diamonds is the result of many considerations. The influence of pavilion depth on diamond cutting: When the pavilion depth is less than 40, the "fisheye effect" often appears, that is, from the diamond table, you can see that there is a white ring on the table, which is black, just like a fish's eye. When the depth of the pavilion is greater than 49, the pavilion has a dark view from the top, resulting in a "black background effect", both of which are manifestations of poor diamond cutting, so special attention should be paid when buying.
(3) Standards for diamond cutting and grading
Generally perfect (good), very good, very good, average.
Width ratio (%) ≤ 50 565 438+0-52 53-66 67-70 765 438+0
Crown height ratio (%) ≤ 8.59-10.51-1616.5-18.5.
Waist thickness ratio (%) 0-0.51-1.52-4.55-7.58
Pavilion height ratio (%) ≤ 39.540-41.41.5-45 45.5-46.547.
Ratio of bottom to top (%) < 2 2-4 4
Depth ratio (%) ≤ 52.5 53.0-55.5 56-63.5 64.0-66.5 67.0
Crown angle ≤ 26.9 27.0-30.5 30.7-37.7 37.8-40.6 40.7.
Diamond price = weight+color+clarity+cut.
You only said the weight is 0.540 carat, and the diamond weighs 0.540 carat, 1 carat = 100 minutes.
54 minutes of training. Weighing more than half a carat, weighing more than 20 points.