A diamond's weight, which is measured in carats—one carat is equivalent to 1/5 of a gram—indicates the size of the stone. Carat is frequently shortened to "ct." A diamond's weight is stated in points (1/100 of a carat) if it is less than one carat. Consequently, a half-carat stone weighs 50 points, whereas a diamond with 75 points is 3/4 of a carat. A diamond's weight is measured in carats and decimals if it is greater than one carat. A 1.07 ct stone, then, weights one carat and seven points. When a diamond's carat weight reaches 50 points, 75 points, or 1 carat, its price typically increases. Frequently, the price difference between a diamond weighing 48 and 49 points is bigger than the price difference between a diamond weighing 49 points and one that weighs 50 points. The rarity of a diamond increases with size. Consequently, the cost per carat rises as the weight of the stone does. For instance, if two stones have comparable cut, clarity, and colour, a 2-ct stone will weigh more than twice as much as a 1-ct stone.

Cut is the factor that fuels a diamond's fire, sparkle and brilliance. An important aspect of the allure of diamonds is the way they sparkle. The sparkle is a result of how a stone is cut - its symmetry, polish, durability, and proportion of its parts - which, in turn, determines how light travels through the stone and back to your eye. Ideally, after light hits the top of a diamond, it travels through the stone and then out the top again, creating the sparkle effect. This sparkle depends on the proportions between the diamond's table size, crown angle and pavilion depth. Many combinations can achieve the same level of sparkle, but what's most important is how these factors work together in your particular stone to create maximum brightness. For example, if a stone's pavilion is cut too shallow or too deep relative to its crown, light might seep from the side or bottom of the stone, thereby reducing the sparkle. Gemologists will study three light effects in your diamond when determining the quality of its cut: brightness, the combination of all white light reflecting from the stone fire, the diamond's colored flashes and scintillation, and the overall pattern of bright and dark areas when the diamond is moved.

Cut is the factor that fuels a diamond's fire, sparkle and brilliance. An important aspect of the allure of diamonds is the way they sparkle. The sparkle is a result of how a stone is cut - its symmetry, polish, durability, and proportion of its parts - which, in turn, determines how light travels through the stone and back to your eye. Ideally, after light hits the top of a diamond, it travels through the stone and then out the top again, creating the sparkle effect. This sparkle depends on the proportions between the diamond's table size, crown angle and pavilion depth. Many combinations can achieve the same level of sparkle, but what's most important is how these factors work together in your particular stone to create maximum brightness. For example, if a stone's pavilion is cut too shallow or too deep relative to its crown, light might seep from the side or bottom of the stone, thereby reducing the sparkle. Gemologists will study three light effects in your diamond when determining the quality of its cut: brightness, the combination of all white light reflecting from the stone fire, the diamond's colored flashes and scintillation, and the overall pattern of bright and dark areas when the diamond is moved.

Due to the intense heat and pressure under which they are created, birthmarks, either internal (inclusions) or exterior (blemishes), are frequently found in diamonds. Diamonds are rarely flawless, like the majority of everything in life. Tiny crystals may become trapped inside of a developing diamond, or the stone may develop surface blemishes. The relative absence of these defects is referred to as clarity. The rarity of a diamond increases with the visibility of its defects. Inclusions, which are imperfections contained entirely within the diamond or mostly within the stone, and blemishes, which are nicks and scratches on the stone's surface, are the two types of flaws or clarity qualities that gemologists will be looking for in your diamond.