When it comes to diamonds, carats aren’t just a unit of weight - they’re a symbol of rarity, value, and natural origin. And in Belgium, one of the world’s most respected diamond trading hubs, that meaning is now being legally protected.
Belgian Law Explained
Under a 2023 Royal Decree, Belgium has made it illegal to sell or certify synthetic diamonds using carat weight. Instead, synthetic stones must be labeled in grams. Natural diamonds, meanwhile, continue to be measured and sold in carats, where 1 carat equals 0.20 grams.
This regulation applies to loose stones, jewelry, and even watches that contain one or more diamonds – natural or synthetic. Businesses are required to disclose key information to consumers, including whether the diamonds are treated, their origin (natural or lab-grown), and their weight.
Why It Matters
The change isn’t just about units of measurement - it’s about protecting the meaning behind “carat” and ensuring transparency for consumers.
Carats have always been tied to the value of natural diamonds, which are formed over millions of years deep within the earth. By contrast, lab-grown diamonds are produced in controlled environments over weeks or months. While they may look nearly identical, their origin stories - and market values - are fundamentally different.
It’s similar to how only sparkling wine made in the Champagne region of France can legally be called Champagne. You can produce something similar elsewhere, but the name carries history, standards, and prestige.
By requiring gram labeling for lab-grown diamonds, Belgium is drawing a clear line - one that protects both the consumer and the heritage of natural diamonds. As lab-grown stones become more common, this kind of clarity may become essential across global markets.
So the question is: Should more countries do the same?
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Download the Official Belgian Royal Decree on Lab-Grown Diamonds (2023)
