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Happiness Guide

Happiness Guide

How are diamond grades determined? Check out the 4Cs of Diamonds to determine

Diamond 4C Evaluation Criteria

Previously, ALUXE introduced GIA diamonds and GIA International Diamond Grading Reports, briefly mentioning that the 4Cs of diamonds are crucial factors influencing diamond grades. However, what are the evaluation criteria for these four factors? Let ALUXE clarify and explain them for you.


 

Diamond "COLOR" Grade

The color of a diamond is a significant factor in determining its value, with diamonds closer to transparent and colorless being more valuable. According to GIA's grading standards, diamonds are classified into different grades from D to Z based on their color after comparison with reference stones.

Transparent and colorless:D、E、F
Near colorless:G、H、I、J
Slightly yellow:K、L、M
Light yellow:N、O、P、Q、R
Yellow:S、T、U、V、W、X、Y、Z


As shown, diamonds below the J grade exhibit noticeable yellow tint. However, what constitutes "slightly yellow"? Unfortunately, we cannot show examples for you to see at ALUXE stores because ALUXE only provides top-quality GIA diamonds of J grade or above, near colorless or colorless.
 


 

Diamond "CLARITY" Grade

Most diamonds have inclusions like minerals or fractures to some extent. However, these inclusions are often difficult to see with the naked eye. Therefore, when evaluating a diamond's natural clarity grade, graders use magnification to examine surface features (blemishes) and internal features (inclusions) based on size, number, position, natural factors, color, and visibility.

Because diamond inclusions can affect light refraction, blocking or distorting light, clarity is an essential feature in diamond evaluation. Common types of inclusions include clouds, feathers, included crystals, and needles. Diamond clarity can be categorized into 11 grades, divided into those that are not visible to the naked eye and those that are visible.

Not visible to the eye:
FL:Flawless
IF:Internally flawless
VVS1/VVS2:Very, very slightly included
VS1/VS2:Very slightly included
SI1:Slightly included
SI2:Moderately included

Visible to the eye:
I1:Included
I2:Very noticeable inclusions that are easily visible to the eye and may affect the durability of the diamond
I3: Highly noticeable inclusions that are clearly visible to the eye and severely impact the durability of the diamond


 

Diamond “CARAT” Grade

Carat, the weight unit of diamonds, is perhaps the most familiar aspect of the 4Cs. One carat equals 200 milligrams or 100 points. Generally, diamond engagement rings are around 30 to 50 points as they are visible and reasonably priced. For those with budget constraints, this can be a reference.
 

 

Diamond “CUT” Grade 

Among the 4Cs, "cut" is the only factor that can be influenced by human craftsmanship. The brilliance of a diamond mainly comes from light refraction and dispersion. The angle of light refraction in diamonds is affected by their cutting depth. Typically, the round brilliant is the most basic cutting style, but there are also variations like brilliant, step, and mixed cuts.

Diamond cut grades can be divided into five levels:
EX: Excellent - Perfectly reflects all incoming light rays into the diamond, extremely rare and perfect diamonds.
VG: Very Good - Reflects fire and brilliance similar to ideal cut.
G: Good - Reflects most of the light and fire into the diamond.
F: Fair - Acceptable level of diamond.
P: Poor - Diamonds that do not meet the standard for fair cut.

 

ALUXE not only does not provide diamonds below the good (G) cut grade but also offers exclusive ALUXE Perfect Cut (PF) diamonds, which account for 1% of diamonds on the market, making them the rarest and most perfect diamonds available.

Diamond Polish

Diamond polish refers to the smoothness of each facet during the cutting and polishing process. This characteristic significantly influences the overall appearance and value of a diamond. Polish grades range from "Poor" to "Excellent," measuring the smoothness of each facet, which affects the diamond's ability to reflect light. High-quality polish subtly enhances a diamond's brilliance and sparkle, while lower-quality polish can result in a dull or hazy appearance, diminishing its overall attractiveness. When purchasing a diamond, it is recommended to choose a "Very Good" or "Excellent" polish grade for the best visual effects.

In the GIA grading system, diamond polish is categorized as follows:
  • Excellent: No visible polish flaws under 10x magnification.
  • Very Good: Polish flaws are very difficult to perceive under 10x magnification.
  • Good: Polish flaws are somewhat difficult to perceive under 10x magnification.
  • Fair: Polish flaws are noticeable under 10x magnification.
  • Poor: Polish flaws are very noticeable under 10x magnification.

During the polishing process, tiny surface imperfections may arise, such as tiny crystal fragments produced by the polishing wheel's drag. These flaws affect the smoothness of the diamond's surface, thereby affecting its ability to reflect light. Therefore, polish is one of the important factors in assessing the overall finish of a diamond.
 
Diamond Symmetry

Diamond symmetry is a crucial factor in evaluating cutting quality, referring to the precise arrangement and intersection of each facet of the diamond. Symmetry affects how the diamond interacts with light, thereby influencing its brilliance and fire. Major gemological laboratories like GIA typically grade symmetry from "Poor" to "Excellent." For diamonds seeking optimal brilliance and fire, it is recommended to look for "Very Good" or "Excellent" symmetry grades. Diamonds with higher symmetry grades usually command higher prices due to the higher level of craftsmanship required.
 
Diamond Fluorescence

Diamond fluorescence refers to the visible light emitted by a diamond when exposed to invisible ultraviolet (UV) light.
In GIA diamond grading reports, fluorescence refers to the strength or intensity of a diamond's reaction to long-wave UV light, which is a significant component of daylight.
The duration of fluorescence is the same as the time the diamond is exposed to UV light sources.

After reading the detailed introduction to the 4Cs of diamonds above, do you have a clearer understanding of the standards for measuring diamonds? Even if it still seems somewhat confusing, don't worry! ALUXE diamonds all come with GIA International Diamond Grading Reports, so you can confidently purchase diamond products from ALUXE without worrying about buying inferior quality.
 

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HOME Happiness Guide Guide to Diamonds How are diamond grades determined? Check out the 4Cs of Diamonds to determine