diamond is a standardized product. Its value is determined by the diamond grade, namely: diamond carat weight (Carat), color (Color), clarity (Clarity), cut (Cut) 4C grade and fluorescence grade. Only diamonds that have undergone strict 4C grade and fluorescence grade evaluation can know their true value; the current internationally accepted grading standard is the grading standard of GIA (Gemological Institute of America). The following is the classification standard for diamond grades:
. Carat weight (Carat)
Diamond weight is calculated in carats (CT). 1 carat = 0.2 grams = 100 points. 0.5 carats = 50 points, 30 points = 0.3 carats. The value of a diamond increases in an irregular geometric progression as the weight of the diamond increases, which is called the carat step. Generally speaking, only diamonds weighing more than 50 points begin to have collection and investment value. The following is the diameter table corresponding to diamonds of different sizes:
(standard round diamond weight and diameter comparison table)
Diamond size comparison diagram:
(diamond size comparison table) Compare the hands-on pictures)
2. Diamond color (Color)
A perfect diamond is colorless or nearly colorless. The value of a diamond is determined by how close it is to colorless. The closer it is to colorless, the higher its value. ( fancy color diamonds exceptions, such as pinks and blues outside the color range)
GIA's diamond color grades are the industry standard. The color grades start from the letter D (representing colorless) and are divided into D, E, F, G, H, I, J, K, L, M, N...Z grades in descending order. Arrange all the way up to the letter Z (light yellow or brown, gradually darker colors).
(diamond color grade diagram)
D level: completely colorless. The highest color grade, extremely rare.
E level: colorless. Only gem identification experts can detect trace amounts of color. It is a very rare diamond
F grade: colorless. Small amounts of color can only be detected by jewelry experts, but are still considered colorless. It is a high quality diamond.
G—H level: nearly colorless. Has a slight tint when compared to higher color grade diamonds. But diamonds of this color grade still have high value.
I-J level: nearly colorless. Slight color is detectable. Higher value.
K-M level: darker color, fire color and worse.
N-Z level: darker color, poor fire.
Diamond color comparison chart:
3. diamond clarity (Clarity)
Diamond clarity refers to the cleanliness of a diamond. The evaluation of diamond clarity includes the degree of internal inclusions and surface features, including the identification of the number, size, visibility, type, location and impact of the above features on the overall appearance of the diamond. Although there are no absolutely flawless natural diamonds in the world, the higher the clarity, the higher the value.
The internationally accepted diamond clarity grades are divided into 6 categories and 11 levels. From high to low, they are: Flawless (FL), Internally Flawless (IF), Very Slightly Included (VVS1, VVS2), Slightly included grade (VS1, VS2), slightly included grade (SI1, SI2), included grade (I1, I2, I3).
(Diamond Clarity Grading Chart)
Flawless Level (FL) Flawless.
Internally Flawless (IF) diamonds have no visible inclusions and may have a few surface blemishes that can be removed by re-polishing.
Very Slightly Included (VVS1 and VVS2) diamonds have only a few tiny inclusions visible inside.
Slightly included grades (VS1 and VS 2) have tiny inclusions visible inside the diamond.
Slightly included grade (SI1 and SI2) diamonds have visible inclusions. SI1 grade diamonds usually have no blemishes visible to the naked eye, while SI2 grade diamonds are likely to have blemishes visible to the naked eye.
Included grade (I1, I2 and I3) diamonds have clearly visible inclusions that are likely to affect the diamond's transparency and brilliance.
( and above are all observed under a 10x magnifying glass )
(actual comparison of diamond clarity grades)
4. Diamond Cut (Cut)
Cut is an important factor in determining the fire, sparkle and brightness of a diamond, good Only the cut can reveal the brightness and fire of a diamond. On the contrary, if the cut is not good, the diamond may look dull.
Diamond cut includes three aspects: cutting proportion, symmetry and polishing, which are divided into EX (Excellent, perfect), VG (Very good, very good), G (good, good), F (faint, average), P (poor, poor).
( The proportion determines the brilliance of the diamond, symmetry refers to the arrangement of the diamond's facets, and polishing indicates the smoothness of the diamond surface )
The most recommended "3EX" cut in the industry, which means Cut Grade (diamond cut) / Polish (diamond polish) / Symmerty (diamond symmetry) are all the best Excellent grades.
(Diamond Cut Grade Table)
Ideal Cut (EXCELLENT): Reflects almost all the light entering the diamond.
VERY GOOD: It can make the diamond reflect light similar to the standard grade cut, and the price is slightly lower.
Good Cut (GOOD): Reflects most of the light that enters the interior of the diamond.
Fair cut (FAIR): The light reflected by the diamond is not as good as that of the G-level cut, and the fire is poor.
Poor cut (POOR): Diamond cuts are either deep and narrow or shallow and wide, which can easily allow light to escape from the sides or bottom, causing the diamond to lose its brilliance.
A poorly cut diamond not only has poor brilliance and lack of sparkle, but also has a smaller diameter. A 1-carat diamond may even look like a 90-point diamond.
five. Diamond fluorescence
refers to whether a diamond glows under ultraviolet light. In most cases, we cannot feel it. Only under relatively strong sunlight, we can feel the presence of fluorescence with the naked eye for diamonds with strong fluorescence.
In recent years, the intensity of diamond fluorescence has had a great impact on diamond prices, and is sometimes higher than other diamond grade standards;
GIA is divided into N (none), F (weak), and M (medium) according to the intensity of diamond fluorescence. ), S (strong), VS (very strong), these are the levels.
When the fluorescence level is at the "Strong (S)" level, the diamond's fluorescence may add a hazy or greasy feeling to the diamond, affecting the diamond's brightness. Generally speaking, the stronger the fluorescence, the lower the price.
recommends choosing fluorescent diamonds of M and above. Most diamonds with strong fluorescence look hazy under the light and feel unclean.
Tips: Whether the diamond milk coffee green
is a milk coffee diamond will not be displayed on the certificate, but it can be distinguished by the naked eye.
milk: It looks foggy, like there is a layer of oil, and it doesn’t shine.
coffee: Diamonds have a coffee tone.
green: Diamonds have a light green color.
choose no milk, no coffee, no green diamond !
