Understanding Grams and Carats: A Guide for Jewelers and Scientists
What Is a Carat? The carat (ct) is a unit of mass used primarily for weighing gemstones and pearls. One metric carat is defined as exactly 200 milligrams, or 0.2 grams. This standard was adopted internationally in 1907 and remains the universal benchmark for gemstone valuation.
Why Carats Matter for Gemstones: Gemstone prices scale exponentially with carat weight. A 2-carat diamond is worth far more than twice the price of a 1-carat diamond because larger stones are exponentially rarer. Accurate conversion between grams and carats is essential for appraisers, jewelers, and buyers to verify the true mass and market value of a gemstone.
The Difference Between Carat and Karat: Carat (ct) measures mass. Karat (kt or K) measures gold purity. 24-karat gold is 99.9% pure. This distinction is a common source of confusion, especially in jewelry retail.
Grams to Carats Quick Reference: 1 gram = 5 carats. 0.5 grams = 2.5 carats. 2 grams = 10 carats. 5 grams = 25 carats. Always use a digital scale with 0.001 g precision for gemstone weighing.
Practical Tip for Buyers: If a jeweler quotes a gemstone in grams, convert immediately to carats to compare market prices. Use ConvertNow's gram-to-carat converter for instant, accurate results without manual math.