The characteristic most commonly-quoted about gemstones, diamonds in particular, is their carat, so it's useful to understand what this is actually referring to. Carats are the unit of mass used to weigh gemstones. One carat is 200mg (milligrams) or 0.2g (grams). You will also see gemstone weight referred to in points. A point is equal to 1/100 of a carat, hence a 75 point gemstone is the same as 0.75 carat.
Carats are a measurement of weight not size. It's important to remember this fact over any other. Some stones may be denser than others of the same size and therefore weigh more - in fact it is this weight difference that can help gemologists to identify the stone type.
It is difficult for buyers to visualise a stone, however, with a size in mind, so for convenience, gemstone dimensions are often given in millimeters (mm) for describing their general sizes and shapes.
More Carat Facts
- Carat is often seen abbreviated as ct.
- Carat should not to be confused with karat which refers to the pureness of gold and gold alloys.
- Carats are the characteristic most used to set the price of diamonds.
- As the size and carat weight of a diamond increases, usually so does its price (due to the stones' rarity).
- Half-carat diamonds are very popular as buyers can get a reasonable sized stone within a reasonable budget.
- The price of a diamond does not increase in proportion to its weight. One carat diamonds are in high demand and in short supply, so the price increase for these larger diamonds is not relative to their size.
- A well-cut diamond can appear bigger than a diamond with more carats or points.
Find out more about the other Cs:
Diamond Colour |
Diamond Caret |
Diamond Clarity |
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helping you to find out more about gemstone carat (ct).