Lab-grown diamonds, like natural diamonds, are rated and graded based on several factors to determine their quality and value. The main ratings and grades used for lab-grown diamonds are:
- Cut: The cut of the diamond refers to how well it has been shaped and faceted. The quality of the cut significantly impacts the diamond's brilliance and sparkle. The most common cut grades are Excellent, Very Good, Good, Fair, and Poor.
- Colour: Lab-grown diamonds are graded on a colour scale ranging from D (colourless) to Z (light yellow or brown). The closer the diamond is to colourless (D, E, F), the higher its colour grade and value.
- Clarity: Clarity is a measure of the presence of internal and external flaws or inclusions in the diamond. The clarity scale ranges from Flawless (no inclusions visible under 10x magnification) to Included (inclusions visible to the naked eye). Common clarity grades include Flawless, Internally Flawless, VVS1, VVS2, VS1, VS2, SI1, SI2, I1, I2, and I3.
- Carat Weight: The carat weight refers to the size of the diamond, with one carat equaling 200 milligrams. Larger carat weights generally increase the diamond's value, but other factors such as cut, colour, and clarity also influence the overall rating.
- Certification: Lab-grown diamonds are typically accompanied by grading certificates issued by reputable gemological laboratories such as the Gemological Institute of America (GIA), International Gemological Institute (IGI), or other recognised institutions. These certificates provide an objective assessment of the diamond's quality and characteristics.
It is essential to consider all these factors when purchasing a lab-grown diamond to ensure that it meets your desired specifications and preferences. The combination of cut, colour, clarity, carat weight, and certification determines the overall rating and value of the lab-grown diamond.