Where the world comes to find
out about diamonds

Calibration Charts

Calibrated Size Charts for various types of gemstones set into standard jewellery mountings

Most gemstones are sold in specific calibrated sizes. The idea here is that the stones will fit standard commercial jewellery such as rings, bracelets, necklaces and earrings. However this does not mean that one has to have a specific size. Most jewelers can accomodate an unusual sized diamond and provide a fitting for it.

The main reason that diamonds are sold in specific calibrated sizes is that it is economically easier to produce gemstones that fit into standard settings. Custom made setting involve more labor and therefore a higher cost and expense. This should be kept in mind when buying a loose diamond or loose stones for settings. Having said that, a diamond, or any other gemstone, does not need to be exactly the right size. A professional jeweler can ensure a setting fits by modifying it slightly to accomodate the gemstone. Variations such as .1 imm for under a carat and .2 mm for over a carat can be accommodated easily.

The weights given here are a guide only. They are for diamonds cut to specific proportions. You will find that colored gems are usually cut slightly larger than diamonds. and so will weight a bit more than is shown on the charts below. The density of a gemstone also affects the weight of course with diamonds being the heaviest.

The list is very much a guide and is made available to give one an idea of the type of weights one would have for each setting.

Oval Cut
Size in mm
5x3 6x4 7x5 8x6 9x7 10x8 11x9 12x10 14x12
Amethyst
.23 .45 .85 1.25 1.75 2.40 3.20 4.50 6.50
Diamond
.25 .50 .75 1.40 2.00 3.00 4.00 5.00 8.00
Emerald
.25 .52 .85 1.26 1.90 2.60 3.75 5.00 7.50
Opal
.16 .28 .47 .78 1.10 1.65 2.15 3.00 4.00
Peridot
.28 .50 .95 1.35 2.00 2.50 3.50 4.00 6.00
Ruby
.35 .60 1.06 1.55 2.20 3.15 3.80 6.00 7.25
Sapphire
.35 .60 1.00 1.55 2.20 3.15 3.80 6.00 7.25
Topaz
.28 .57 1.10 1.60 2.50 3.50 4.50 6.00 8.80
Round Cut
Size in mm
2 3 4 5 6 6.5 7 8 10
Amethyst .04 .10 .20 .40 .70 1.10 1.30 1.80 3.30
Diamond .03 .10 .23 .47 .80 1.00 1.25 1.90 3.50
Emerald .04 .12 .27 .48 .80 1.26 1.70 2.50 6.10
Opal .02 .09 .16 .34 .57 .75 .83 1.30 2.00
Peridot .05 .12 .26 .50 .85 1.11 1.25 2.00 5.25
Ruby .05 .15 .34 .65 1.05 1.41 1.60 2.25 4.50
Sapphire .05 .15 .34 .65 1.05 1.41 1.60 2.25 4.50
Topaz .04 .11 .30 .56 1.00 1.36 1.55 2.50 5.75
Pear Cut
Size in mm
5x3 6x4 7x5 8x6 9x6 10x7 12x8 14x9
Amethyst
.20 .35 .65 .85 1.25 1.70 4.00 5.00
Diamond
.25 .50 .75 1.00 1.50 2.00 3.50 5.00
Emerald
.25 .45 .70 1.05 1.70 2.60 4.15 6.10
Opal
.13 .22 .35 .50 .70 1.03 1.40 2.45
Peridot
.25 .45 .70 .80 1.10 1.40 3.40 4.75
Ruby
.30 .50 .75 1.00 1.85 2.50 4.75 7.90
Sapphire
.30 .50 .75 1.00 1.85 2.50 4.75 7.90
Topaz
.25 .50 1.00 1.10 2.00 3.50 6.50 8.50
Octagon/Emerald Cut
Size in mm
5x3 6x4 7x5 8x6 9x7 10x8 11x9 12x10 14x12
Amethyst
.35 .55 1.10 1.60 2.25 2.90 4.20 5.60 7.25
Diamond
.25 .50 1.00 1.50 3.00 4.00 5.00 7.80 8.80
Emerald
.30 .60 .90 1.80 2.31 3.15 4.50 5.25 5.80
Peridot
.35 .60 1.00 1.70 2.25 3.80 5.25 6.25 8.80
Ruby
.55 .75 1.15 1.60 2.30 2.75 4.00 6.25 9.00
Sapphire
.55 .75 1.15 1.75 2.30 2.75 4.00 6.25 9.00
Topaz
.40 .65 1.25 2.40 3.40 4.00 5.75 8.00 9.50
Marquise Cut
Size in mm
4x2 5x3 6x3 7x3.5 8x4 10x5 12x6 14x7
Amethyst
.10 .15 .20 .34 .48 .90 1.59 2.45
Diamond
.12 .18 .25 .37 .50 1.00 2.00 3.00
Emerald
.09 .19 .30 .45 .60 1.40 1.80 2.80
Opal
.09 .13 .17 .27 .37 .59 1.00 1.25
Peridot
.10 .17 .25 .37 .50 1.00 2.00 2.55
Ruby
.13 .24 .35 .55 .75 1.15 2.20 3.00
Sapphire
.13 .24 .35 .55 .75 1.15 2.20 3.00
Topaz
.07 .17 .30 .50 .70 1.20 2.00 3.40

Top

Who Are We | Disclaimer | Feedback | Link to Our Site | Diamond Links | Terms

Copyright © 2006-2020 ALL RIGHTS RESERVED. Technical Author Services Pty Ltd. ACN. 126 773 126. ABN 62 122 488 508 A private limited company incorporated in Victoria, Australia.
Webmaster: Technical Author Services Pty Ltd

Design a Mobile Website
View Site in Mobile | Classic
Share by: