Diamond Carat Weight
Understanding Diamond Carat Weight
Diamond carat weight serves as a crucial metric measure, defining the weight of a diamond. It is important to note that 1 carat is equivalent to 0.20 grams, and much like a pound is divided into 100 pennies, a carat is divided into 100 points. When referring to a diamond, if it weighs half a carat, it will be expressed as 0.50cts. The carat weight is a key determinant of a diamond's value.
Diamond Carat Weight vs. Physical Size
It's essential not to confuse diamond carat weight with the physical size of the diamond. While it's logical to assume that an increase in carat weight corresponds to a larger diamond, these are distinct characteristics. Carat weight and measurement relate to an increase in the quantity of diamonds, but both remain separate units of measurement—one related to weight and one to size.
The Origin of Diamond Carat Weight
The term 'Carat' originates in the Greek word for the 'Carab' plant, whose seeds were consistently used to measure weight. Carob seeds weighing nearly 1 carat with minimal variation were employed with balance scales to determine diamond carat weight. Their consistent weight made them a reliable measure in the historical assessment of diamonds.
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The Origin of the Carob Seed
Expressions of Diamond Carat Weight
Diamond carat weight was legally established with the introduction of the Weights and Measures Act of 1963. The Metric Carat weighs 200 milligrams, 0.20 grams, or 1/5 metric gram. Alternative expressions include:
Decimal Weight: Conventionally expressed to two decimal places, a half-carat diamond is denoted as 0.50cts.
Fractional Carat Weight: Expressed in fractions, with 1/4 carat representing 0.25cts or a quarter of a carat.
Points: Used for weights below a full carat, one carat divided into 100 points. For instance, half a carat is expressed as 50 points.
Grains: A measure of weight, especially associated with pears. A grain represents a quarter of a carat or 0.25cts, with diamonds near these weights termed grainers.
Melee: Refers to small groups of diamond sizes.
Number of Diamonds per Carat: Expresses the approximate diamond size based on the number of diamonds that make up a carat in a specific size bracket. For example, 6pc (six per carat) diamonds are individually 0.16cts in weight.
Diamond Carat Weight Compared to Gemstones
The specific gravity of a diamond varies compared to other gemstones. As a result, the weight of a similarly sized and proportioned gemstone can be calulated. Find out how to do this in our detailed blog post on Diamond, Sapphire and gemstone weights compared.