Diamond Weight: Carat. Diamond Size Chart & Measurements, Carat Weight Buying Guide
The measuring unit is the metric carat, which corresponds to the fifth of 1 gram, that is to say 2 decigrams.
Thus 1 carat = 0.20 gram.
The balance must be well installed under shelter:
- draughts (to be avoided)
- heat sources
- vibrations (anti-vibratory table)
The stone must be clean.
Be careful with the precision of the balance:
- Set or reset to zero
- Weighting in vacuum (to be more accurate
- Weighting
Results:
- In many major diamond-trading countries and international industry organizations, a diamond's weight can only be rounded up to the next higher hundredth from nine thousandths of a carat.
- Following this convention, a stone which weighs 1.568 carat would be rounded to 1.56 carat; but one which weighs 1.569 carat would be rounded to 1.57 carat.
Calculating brilliant cut diamond: Diameter/Weight.
This unit of weight does not have anything to do with the karats of gold alloys.
The carat is divided into 100 points (hundredths of metric carat), in other words, a loose diamond of 0.25 carat has 25 points. The same thing applies to the other precious stones, example: a sapphire of 1.15 carat weighs 1 carat and 15 points.
One uses various kinds of balances to obtain the weight of these precious stones. We invite you to click on the link to hereafter discover the principal balances which one can find in the trade: carat balance.
Carat Weight & Diameter for Round Brilliant Diamonds
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| 0.03 carat | 0.05 carat | 0.07 carat | 0.10 carat |
| Ø 2.00 mm | Ø 2.50 mm | Ø 2.70 mm | Ø 3.00 mm |
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| 0.15 carat | 0.20 carat | 0.25 carat | 0.33 carat |
| Ø 3.40 mm | Ø 3.80 mm | Ø 4.10 mm | Ø 4.40 mm |
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| 0.40 carat | 0.50 carat | 0.65 carat | 0.75 carat |
| Ø 4.80 mm | Ø 5.20 mm | Ø 5.60 mm | Ø 5.90 mm |
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| 0.85 carat | 1.00 carat | 1.25 carat | 1.50 carat |
| Ø 6.20 mm | Ø 6.50 mm | Ø 7.00 mm | Ø 7.40 mm |
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| 1.75 carat | 2.00 carat | 2.25 carat | 2.50 carat |
| Ø 7.80 mm | Ø 8.20 mm | Ø 8.60 mm | Ø 9.00 mm |
Weight of a gemstone according to size and shape cut
To have a realistic estimate of the weight (in carat) of a gemstone just use the simulator below by following these instructions:
- Select from the list a gemstone.
- Select from the list a cut shape.
- Indicate a Length (in millimeters) or a diameter (if your stone is round).
- Indicate a Width (in millimeters) or a diameter (a second time, if your stone is round).
- Indicate a Depth (in millimeters).
- Click on the button Calculate >>.
There may be significant weight differences between the weight estimated by our simulator and the actual weight of the gemstone, especially regarding color stones because cut shapes are not standardized.