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What Are The 4Cs?

Written by Sakura Hashimoto


Posted on April 22 2023

Like natural diamonds, lab grown diamonds are valued using the 4C world standard, which is based on criteria created by the GIA (Gemological Institute of America), and refers to Cut, Clarity, Color, and Carat. All of these factors affect the appearance and quality of a diamond (including lab grown diamonds).

Cut (Brilliance)
The overall proportions of the diamond and the size and position of the facets make up the cut. The consistency and balance of these factors greatly affect the way the stone catches and reflects light to the eye.

The optimal proportions of a diamond cut are studied to maximize brilliance. If the cut falls within these criteria, it is considered an ideal cut.

One of the factors that determines a diamond's value is its color. The more colorless and transparent the stone is, the more valuable it is. However, fancy colored diamonds retain their yellow, brown, pink, and other colors and are often quite rare in the natural diamond world, which is why they are often more expensive. All diamonds are graded by experts according to the GIA diamond scale, with grades ranging in color from D (clear and colorless) to Z (light yellow) in descending order. In addition to lab grown diamonds, which allow us to offer better quality stones at reasonable prices, MIAYMA also offers a selection of fancy colored lab grown diamonds, which are extremely rare and valuable in the natural diamond world.

The clarity of a diamond is measured by the presence or absence of flaws. Small surface scratches and internal inclusions (microscopic inclusions) are extremely common in diamonds. They are usually only visible under magnification, but they change the brilliance of a diamond and affect its value. The fewer the inclusions, the more valuable the diamond.

FL: Flawless
IF: Minute surface features
VVS1, VVS2: Minute inclusions 
VS1, VS2: Very, very slight inclusions (difficult to see under 10x magnification) 
SI1, SI2: Slight inclusions (visible under 10x magnification) 
I1, I2, I3: Inclusions visible to the naked eye

At MIYAMA, we only deal in stones with almost perfect clarity grade (VVS1-2), and all lab grown diamonds come with a certificate of authenticity from a third-party certification body.

Carat (Weight)
Carat refers to the weight of a diamond, and it is said that about 250 tons of ore must be mined to extract a natural diamond of one carat. Therefore, due to their rarity, larger diamonds are more valuable.

However, it is now possible to make diamonds in laboratories (hereafter referred to as "lab grown diamonds"), and they are now available at a much more reasonable price compared to natural diamonds. Since lab grown diamonds are chemically, physically, and optically identical to natural diamonds, their value is determined by the same 4Cs.