How It Works
GemSize.org is, as the name implies, all about gemstone sizes. Its main purpose is to show you the actual size of any gemstone directly on your screen, letting you simulate how a real gem would look on a ring and finger.
You can compare 36 gemstones in 13 shapes and 33 colors. The platform supports weights from 0.05ct to 40ct and sizes from 0.1mm up to 40mm.
Dimensions are optional (length and/or width), but if you leave them out, they will be automatically calculated using standard shape formulas. Bear in mind that these formulas provide only rough estimates, so if you know the exact dimensions, it's always best to enter them.
Because diamonds have a high refractive index, they can be cut with proportions that maximize light return and brilliance. Colored gemstones, including fancy colored diamonds, are typically cut with different proportions to help enhance their natural color. Since colored gemstones are usually cut deeper, this is taken into account when calculating their face-up sizes.
Most gems have a variable specific gravity depending on their chemical composition. In such cases, this website will use a standard average most commonly accepted for jewelry-grade specimens. For example: The standard specific gravity for Almandine (member of the Garnet family) is somewhere between 3.95 and 4.20, with about 4 to 4.1 being typical. For calculations, this site uses 4.05.
Did you know: Gold (SG: 19.3) is significantly heavier (denser) than any gemstone.
You can save any chart to your device as an image or download it as a PDF. PDFs are especially useful if you want to print at actual size to cut out the shapes for a try-on.
P.S.: Printing image(PNG) charts will not give you accurate (true-to-scale) sizes - for printing at actual size, stick to PDFs.
You can compare 36 gemstones in 13 shapes and 33 colors. The platform supports weights from 0.05ct to 40ct and sizes from 0.1mm up to 40mm.
How To Start
To get started, use the form at the top of every page. There, you can select weight(ct), gem, shape, color, and size, then view the selected gem in the simulator - either as a side-by-side comparison or as a single gem view.Dimensions are optional (length and/or width), but if you leave them out, they will be automatically calculated using standard shape formulas. Bear in mind that these formulas provide only rough estimates, so if you know the exact dimensions, it's always best to enter them.
Cut Proportions
Cut proportions for a given shape are assumed to be the same across all gemstones, with one exception: white diamonds. These use a more advanced algorithm, originally developed for diamdb.com - my other website, specialized exclusively in colorless diamonds.Because diamonds have a high refractive index, they can be cut with proportions that maximize light return and brilliance. Colored gemstones, including fancy colored diamonds, are typically cut with different proportions to help enhance their natural color. Since colored gemstones are usually cut deeper, this is taken into account when calculating their face-up sizes.
Specific Gravity
One of the most important factors determining a gem's physical size is its specific gravity. Specific gravity measures the density of a substance, in this case gemstones, compared to the density of water. It tells you how heavy a gem is compared to an equal volume of water. For more info, check out this concise video explanation.Most gems have a variable specific gravity depending on their chemical composition. In such cases, this website will use a standard average most commonly accepted for jewelry-grade specimens. For example: The standard specific gravity for Almandine (member of the Garnet family) is somewhere between 3.95 and 4.20, with about 4 to 4.1 being typical. For calculations, this site uses 4.05.
Did you know: Gold (SG: 19.3) is significantly heavier (denser) than any gemstone.
Can't Find Your Gem?
If the gem you would like to explore is not available in the dropdown list, you have a couple of options, depending on whether or not you have the exact dimensions:- If you have the exact dimensions, choose any gem in the same color as the one you are interested in. The simulator will display the exact dimensions you enter, regardless of which gem is selected.
- If you don't have exact dimensions but want to see an approximate size, choose a gem with a similar specific gravity. This will give you a rough idea of the actual size at a specified weight. For reference, check specific gravity chart.
Size Charts
To quickly compare sizes of the same shape, use size charts. There are currently 468 interactive charts available, each showing estimated sizes for a selected gemstone and shape, ranging from 0.25 to 40 carats, all on one page.You can save any chart to your device as an image or download it as a PDF. PDFs are especially useful if you want to print at actual size to cut out the shapes for a try-on.
P.S.: Printing image(PNG) charts will not give you accurate (true-to-scale) sizes - for printing at actual size, stick to PDFs.