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How to Measure an Uncut Diamond

Diamonds, including uncut stones, are measured by their weight. Because diamonds have a long and specialized history, standard units of measurement are not used. Rather, diamonds are measured in units called carats. One carat is equal to 200 milligrams, or .2 grams. The term "carat" likely originates from the carob bean, which was once used to measure diamonds. Larger diamonds are increasingly rare, thus higher-carat diamonds are worth more.

Things You'll Need

Extremely sensitive scale, preferable a jewelry or diamond scale

Instructions

- 1
  Acquire a specialized scale. The scale must be extremely sensitive and accurate to the milligram. There are specialty jewelry and diamond scales designed for this purpose. There are also scientific scales that might work.
- 2
  Test and align the scale according to the owner's manual for the scale.
- 3
  Clean and clear the scale. The weights that will be measured are so small that even normal dust and debris might impact your results.
- 4
  Place the uncut diamond on the scale. Typically the diamond should be on the center of the scale, although the specific scale may require different placement.
- 5
  Obtain a weight measurement. This measurement should be in milligrams. Weigh the diamond multiple times to ensure accuracy.
- 6
  Convert the weight to carats by dividing the number of milligrams by 200. For example, a 300 milligram diamond would be 1.5 carats.

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