When buying a lab grown diamond with an IGI certificate, the same 4C's apply as they do with natural diamonds: cut, colour, clarity, and carat weight. Here’s a quick guide:
- Cut: Impacts sparkle the most. Choose “Excellent” or “Ideal” cuts.
- Colour: For a white diamond, opt for colour grades D–F (collection colours).
- Clarity: VS1 or higher gives you a clean look, often without visible inclusions.
- Carat Weight: Lab diamonds allow you to go bigger for less.
The IGI has also introduced Light Performance Analysis, a scientifically grounded assessment of a diamond’s sparkle. It measures brightness, fire, and contrast, to complement the traditional 4C's.
Starting from the later part of 2025, when buying a lab grown diamond with a GIA certificate, it will no longer state the 4C's. Instead, diamonds will be categorised into two simplified tiers “premium” or “standard” based on combined evaluations of colour, clarity, and finish. Diamonds failing to meet minimum quality thresholds may receive no designation at all.
