How to Estimate
Gemstone Carat Weight

© by Mary Harvey; all rights reserved

How do you find out the carat weight of gemstones?

Say you found this awesome gemstone that you can't wait to wire wrap, but you have no idea how many carats the stone weighs.

Here are two easy methods for weighing both natural and lab created gemstones:

Gem Scale

The simplest way is to get a gem scale that weighs in carats. These scales also weigh in grams. Just select "carats" and put your stone on the scale. Viola - carat weight.

Most of the less expensive gem scales weigh up to 50 grams.

Postage Scale

But what do you do if you have a larger stone that is too big for the scale? Try this:

Use a postage scale, or any scale that weighs in ounces. One ounce equals 28.4 grams. Weigh the stone, convert ounces to grams, then multiply the grams by 5 to get the estimated carat weight.

Example:

Your gemstone weighs 2 ounces on a postage scale. Multiply ounces times 28.4 grams, then multiply the total by 5 to find the carat weight:
2 ounces x 28.4 grams per ounce = stone weight of 56.8 grams
56.8 grams x 5 = stone weight of 284 carats

This method is not quite as accurate as a gem scale, but it will get you close to the true carat weight of the stone.

What to Do with the
Carat Weight

Let customers know the carat weight of the gemstones in your jewelry by listing this information on your jewelry tags or cards.

Mary Harvey is the owner of Custom Jewelry Supply, specializing in tools for wire working and beading, large gemstones for wire wrappers, cameos of all types, birthstones and snapsets, standard and designer cabochons, and more. Mary is also a jewelry artist.