It is important to know the weight of a gemstone, particularly if you want to be able to compare carat to gram measurements and make informed purchasing decisions. The standard unit in the gemstone business is carat. 1 carat is equal to 0.2 grams. Grams are often used for bulk weight calculations. This guide explains the main differences between carat and gram to help buyers correctly assess gemstone size, value and price. Whether you are buying diamonds, sapphires or other precious gemstones, knowing this conversion will prevent confusion and overpricing. Learn how the weight of a gemstone can impact its quality, price per carat and overall investment value in the global gemstone market so that you can make better buying decisions.