Instructions
Understand what a carat is. A carat is a simple scale given to diamonds that assesses its weight. Typically, a 1.00-carat diamond weighs in at 0.2 grams. The more carats a diamond possesses, the higher in value it becomes.
Inspect the cut of the diamond. A diamond's cut is the way a diamond cutter has actually turned a rough stone into a brilliant diamond. A brilliantly cut diamond will sparkle brightly and transfer colors from one angled cut to the next to create a fire-like appearance.
Identify the color of a diamond. A diamond's color is crucial to its value. Colorless stones are very rare and are graded in the "D" category. Other categories include diamonds in varying colors such as green, blue and yellow. These are called fancies and are extremely rare and expensive, with red being the most prized.
Search for inclusions in the diamond. Inclusions are often referred to as nature's fingerprints. These are deposits in the stone that affect its ability to transfer color from one facet to another. The more inclusions a diamond has, the lower it is graded.