There are roughly 200 different gemstones that exist in nature today. Gemstones are valued for their supreme brilliance and color. Whether you're choosing a gemstone for its "magical properties", because it's your birthstone, or it matches you or your loved one's eyes - At Iris & Mill, we want to help you choose the right gemstone for you and help you learn more along the way.


Gemstone characteristics are similar to the characteristics used to classify and describe diamonds (think the 4 C's). There are several key differences, however, and a few additional attributes specific to gemstones.


Gemstone color is evaluated slightly different than with diamonds. Three characteristics or qualities that separate gemstones are hue, tone, and saturation.


Like diamonds, the cut of a gemstone refers to the facet arrangement (symmetry, shape, etc.) and are cut in a way that ideally displays their color and brilliance.


Gemstone clarity is viewed in a slightly different way than with diamonds. Gems generally form in an environment filled with trace minerals that become trapped in the gemstone. Gemstones are much more prone to these "inclusions", but because of the color richness of gems, these are much more easily masked and not as noticeable.


Gemstones vary in density, so a gem and a diamond with the same carat weight will actually appear visually different in size. You'll often find the gemstones are listed with carat weight AND size in millimeters (mm) for a more accurate representation. 


Did you know that almost every colored gemstone that you see has been enhanced in some way? Enhancements refers to various techniques that improve a gemstones appearance, value, and durability. Untreated colored gemstones are quite rare, and expensive.


We view gemstone color a little differently than we do with diamonds. Three factors help make up the overall color and value of a gemstone - hue, tone, and saturation.


The hue refers to the actual color itself of a gemstone. Now, most gemstones will have two colors - a primary and secondary hue. For example, an emerald has a greenish and yellowish hue or a ruby will have a pink and red hue. The most valuable gemstones, however, are the ones that show a pure primary hue and have very little hints of secondary hues.


The tone of a gemstone's color describes the depth of that color, and it's categorized on an opacity scale with 5 values ranging from light to dark. You can best view the tone of a gemstone when held away from direct light. A "light" tone will show brilliance, even without direct light.


A gemstone's saturation refers to the intensity of the color and is classified on a scale ranging from light to strong to vivid. Vivid gemstones are considered the most valuable. For example, an intense and vivid blue sapphire will have a much higher value than a "faded" blue with light intensity and secondary hues.


The most important factor when considering a gemstone is how much YOU (or your loved one) likes the COLOR. Some gemstones have a beautiful combination of primary and secondary colors that while experts may not deem them "the most valuable", many people fall in love with strong mix of primary and secondary hues. Choose what best fits your eye, personality, and style.


Like with diamonds, cut and shape are often confused but used interchangeably. Cut truly refers to how a gemstone is faceted, polished, and turned (while shape refers to the face up outline). The technique for cutting gemstones is a little different, and more fluid and variable, than with diamonds. Since color is such an important actor when considering gemstones, and gemstone cutter will cut to maximize color, brilliance, and minimize (the more prevalent) inclusions. 


Gemstone color is important, but it's the cut that truly displays a gems beauty. Look for a symmetrical cut that disperses light evenly across the surface, and a cut that matches a gemstones saturation - for example a higher saturated vivid gemstone should ideally have a shallower cut so light can penetrate the gem easier, and a deeper cut for a less saturated gemstone.


diamond clarity grades

Clarity is viewed differently for gemstones than diamonds. For diamonds, we grade clarity on the absence of defects, flaws, or "inclusions". While it's true that in gemstones a more "valuable" gem generally is one that has fewer inclusions or defects, inclusions don't necessarily decrease the beauty or color richness of a gemstone. In fact, in some cases inclusions can actually INCREASE the value and beauty of a gemstone by deflecting light throughout the gem.


Gemstones are classified by the same GIA grades that diamonds are (from I1, I2, I3 to VVS), but they are also classified by type as some gemstones have naturally fewer inclusions than others.


Type I: Usually Eye-Clean

Eye-clean means that inclusions aren't visible with the naked eye. Popular examples of (typically) natural eye-clean gemstones are morganite and tanzanite.

Type II: Usually Included

This type of gemstone will often have naturally occurring inclusions - rubies and sapphires are perfect examples.

Type III: Almost Always Included

This type of gemstone almost always has inclusions (but doesn't necessarily detract from their value) - emeralds are a perfect example.

When shopping for gemstones, keep in mind that the type and grade work together when classifying gems. For example, even a VVS grade on a Type III will still have noticeable inclusions under magnification (but will usually be eye clean).


Gemstones differ from diamonds in that they are measured in carat weight and surface dimensions (in millimeters). The reason for this is that gemstones vary in density and are denser than diamonds. For example, if you compare a one-carat sapphire to a one-carat diamond, the sapphire will APPEAR smaller because it's denser (even though they weigh the same).


Gemstones are often enhanced with a variety of treatments depending on the type of gem and the desired effect. Nearly all gemstones found on the retail market (including those at The Brother's Jewelry Co.) have been enhanced in some way. This is done to enhance color, clarity, and durability.


Heat Treatment: Used to permanently enhance the color and/or clarity of a gemstone by applying a high temperature to a gemstone (the time and temperature depend on the gem). The is completely safe and accepted by the American Gem Trade Association.

Infusion: This is where a gemstone is filled with a material like oil or resin to improve clarity. This is done to improve overall appearance.

Coating: This adds a protective layer to gemstones. Adding a material like wax or resin helps protect a gemstone from oils or damage. Improves durability and appearance, most commonly used on pearls.

Dyeing: A coloring agent is used to enhance a gemstone's color or improve color uniformity. Dyeing only enhances natural pigmentation of a gemstone and will look identical to an undyed natural gem.