How Does the Gemstones Size Chart Affect Your Custom Fine Jewelry?

Gemstones Amethyst

Whenever you begin investigating the purchase of gemstones, you soon discover that the weight or carat value of a gem is used to describe its size. This measurement is based on gemstone weights. But now, you may have come across something called the gemstones size chart, and are wondering why you should take this into account when choosing a gemstone.

In this article, we’ll explain the calibrated gemstone size chart, why it exists, how it will affect your selection, and in which situations you can simply ignore it.

What Are Calibrated Gemstones?

Certain gemstone sizes are considered to be “standard”. These gemstones fit regular settings used in most mass-produced jewelry, and are commonly known as calibrated gemstones. In fact, these stones make mass-produced jewelry possible because manufacturers can produce hundreds – or even thousands – of identical jewelry items easily and efficiently.


Gemstones fitting regular settings used in most mass-produced jewelry, and are commonly known as calibrated gemstones. Click To Tweet

When replacing lost or damaged gemstones for an existing setting, a jeweler can simply choose the calibrated gems that fit the setting, and reset the jewelry item. He or she need only consult the gemstone size chart to get this information.

How Do Unusual Gemstone Sizes Affect Jewelry Pieces?

There are times when a valuable gemstone cannot be cut to a standard size without reducing its value. At times like these, gemstone cutters desire a perfect cut in order to enhance the individual stone. The result is an unusually-sized gemstone.

As you can no doubt imagine, the goldsmith who ultimately sets the stone into a jewelry piece must custom-design a setting for that special stone. In doing so, a skilled professional will seek to design the setting to do more than just hold the stone in place. It will enhance the unique qualities of the stone, showing off its greatest assets.

Thus, if you are commissioning a bespoke piece of jewelry, you can choose any stone you desire, whether standard-sized or not. If you later want to replace a gemstone in your setting, it may not require a new setting size. Goldsmiths can make setting adjustments of 0.2mm or more, depending on the size and shape of your stone.

The Standard Gemstones Size Chart for Specific Gems

Unless you are an expert, you likely won’t know the size of gemstones simply by looking at gemstone weights. After all, the density (or specific gravity) of a diamond will differ from that of a sapphire or an opal. For example, a 6.5mm round diamond, sapphire, and opal all have different carat weights.

Therefore, a gemstone weight chart will not tell you the size of a gemstone unless it includes the type of stone as well as the size of the stone in millimeters.

Here is an example:

Size (round stone) Diamond Sapphire Opal
6.5mm 1 carat 1.14 carat 0.61 carat

Some gemstone charts combine both carat and size. You can look at a diamond carat size chart, sapphire carat size chart, or a ruby carat size chart to see the exact size of the gemstone and its carat value.

Here are some examples:

Round Faceted Gemstones Size Chart and Weight Chart

Applying the Diamond Size Chart to Jewelry from Jaume Labro

Because Labro makes each piece of jewelry by hand, you can choose any diamond sizes you like. However, you will want to know the size in order to get an idea of how your gemstone will look in a piece.

If you choose a 2-carat diamond ring, you will want to know what size you should expect from the diamond. When choosing other precious stones for your jewelry, be aware that size will vary, depending on the density of the gemstone. For example, a 2-carat sapphire will be larger than a 2-carat diamond.

Diamond sizes are important in determining the final design of your fine jewelry ring, but there are other considerations too. For example, a larger diamond with inclusions might even be cheaper than a smaller one with fewer or no inclusions. We’ve summed these criteria up in our article on the four Cs of diamonds.

What’s Most Important When Choosing a Diamond?

Beautiful Ideal Cut White Diamond - Jaume Labro Custom Jewelry

Assuming that you are buying a diamond to wear in a handmade jewelry item, your choice of diamond will be influenced by your personal preferences and expectations.

It’s useful to know the way diamonds are measured and priced, but their ultimate value will be entwined with your most precious memories. Gemstones size chart cannot measure that, nor can monetary value reflect it.


It’s useful to know the way diamonds are measured and priced, but their ultimate value will be entwined with your most precious memories. Click To Tweet

Labro offers a range of magnificent diamonds, sapphires, and other precious and semi-precious gemstones. If you would like assistance in choosing precious stones or selecting a jewelry design to match the stones you desire, please contact us. Our expert gemologists, goldsmiths, and jewelry designers are at your service.

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