When buying colored gemstones, it is sometimes easier to evaluate the unseen stone sizes by comparing them to diamonds cut to similar, standard sizes. For example, if you wanted a colored stone the size of a two caret marquise diamond, according to the chart below you should look for a stone approximtely 12mm x 6mm. Chances are the stone won't WEIGH exactly two carets, but it will be the same SIZE as a two caret diamond.

Scroll down for Automatic Conversion Table.

0.25	4.1		6 x 3	5 x 3	5 x 3	4 x 4	4.5 x 4.5 x 4.5
0.50	5.2	6 x 4	8 x 4	6 x 4	6 x 4	5 x 5	6 x 6 x 6
0.75	5.8	7 x 5	9 x 4.5		6.5 x 4.5	6 x 6
1.00	6.5	8 x 5	10 x 5	7 x 5	7 x 5	6.5 x 6.5
1.25	7.0			7.5 x 5.5
1.50	7.4	9 x 6	11 x 5.5	8 x 6	8 x 6	7 x 7	7 x 7 x 7
2.00	8.2	10 x 7	12 x 6	8.5 x 6.5	8.5 x 6.5	8 x 8	8 x 8 x 8
2.50	8.8	12 x 7	13 x 6.5	9 x 7	9 x 7	8.5 x 8.5	9 x 9 x 9
3.00	9.4	12 x 8	14 x 7	10 x 8	10 x 8	9 x 9	10 x 10 x 10
3.50	10.0	13 x 8	14 x 7.5	10 x 8.5		9.5 x 9.5
4.00	10.04	14 x 8	16 x 8	11 x 9	11 x 9	10 x 10
4.50	10.80	14.5 x 9		11 x 9.5		10.5 x 10.5
5.00	11.20	15 x 9	16 x 8.5	12 x 10	12 x 10	11 x 11

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[To convert from one unit of measurement to another, enter number in the "From" column]

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