Diamond Carat Weight: Points, Grams & Total Weight Explained
One metric carat is 0.2 grams, or 200 milligrams, and contains 100 points. Carat weight describes mass rather than visible size. Confirm whether a number refers to one stone, all diamonds in the jewelry, or an estimate for a mounted stone.
Convert carats, points and grams
GIA defines a metric carat as 200 milligrams. One hundred points equal one carat, so a “75-point diamond” weighs 0.75 ct. The following are unit conversions, not price estimates.
| Carats | Points | Grams |
|---|---|---|
| 0.25 ct | 25 | 0.05 g |
| 0.50 ct | 50 | 0.10 g |
| 0.75 ct | 75 | 0.15 g |
| 1.00 ct | 100 | 0.20 g |
| 2.00 ct | 200 | 0.40 g |
| 5.00 ct | 500 | 1.00 g |
To convert carats to grams, multiply by 0.2. To convert points to carats, divide by 100. Keep the unit beside the number when comparing documents; “0.75” without a unit is incomplete information.
Distinguish the center stone from total carat weight
GIA explains total carat weight as the combined weight of the diamonds in a piece. A listing for a one-carat-total-weight ring does not necessarily describe a one-carat center diamond.
For example, a ring with a 0.70 ct center diamond and 0.30 ct of smaller diamonds has 1.00 ct total diamond weight. The center remains 0.70 ct. This arithmetic does not make the ring equivalent to a solitaire containing one 1.00 ct diamond.
Ask for the center-stone weight and the combined side-stone weight separately. If the item includes colored gemstones, ask exactly which stones the stated total includes.
Use millimeter measurements for visible size
Weight and face-up dimensions are different measurements. Two stones can weigh the same while having different lengths, widths or depths. Compare the millimeter measurements on their reports rather than relying on a generic carat-to-diameter picture.
A stone’s proportions also matter. Greater depth can add weight without providing the face-up dimensions you expect. View the actual jewelry alongside its measurements; neither the weight nor a zoomed product photograph tells the whole story.
For rounds, the round brilliant comparison guide connects measurements with the other report fields.
Ask whether the weight was measured or estimated
A loose diamond can be weighed independently. A mounted piece presents a different question because the setting and other stones are also present. Ask whether its stated diamond weight comes from an existing report, a prior record or a current estimate.
GIA’s appraisal guidance identifies estimated mounted-stone weight as an example of an assumption that should be disclosed. Record that limitation instead of repeating an estimate as an exact measurement.
Bring the jewelry intact. Before authorizing stone removal, discuss why it is needed, the condition of the setting and who would perform the work. A kitchen scale reading for an entire ring is not the center diamond’s carat weight.
Keep weight separate from a purchase amount
A price per carat is meaningful only alongside the actual stone description and the transaction it refers to. Do not multiply a retail listing for a different stone by your diamond’s weight and treat the result as a purchase offer.
Compare the other diamond quality factors, report information, condition and any jewelry included in the sale. A larger weight does not create a guaranteed price multiple, future appreciation or a deadline to sell.
Organize the weights before a Downtown LA visit
Make a short list of the items and attach copies of the matching documents. Separate a confirmed loose-stone weight from a total-weight description or an estimate. This makes it easier to discuss several rings, loose stones or a larger collection without mixing their records.
Cash 4 Gold & Diamonds buys natural polished diamonds and diamond jewelry at 617 S. Hill Street, Los Angeles, CA 90014. Any size and shape are welcome; we do not buy laboratory-grown, uncut or rough diamonds. Contact us with what you have and ask about an evaluation and payment arrangements.
Are carat and karat the same?
No. Carat is a gemstone weight unit. Karat describes the gold proportion of a gold alloy. Keep the stone weight and the metal description separate on your item list.
Can I discuss selling a diamond without its report?
Yes. Describe the item and any missing paperwork when arranging the evaluation. Ask which information can be established from the actual piece and whether additional documentation would be useful before paying for it.