Gemstones

This guide defines the five essential characteristics of gemstone quality. By understanding these characteristics, you'll be able to shop with confidence. Print this helpful list and take it with you shopping so you can make the best choice on a beautiful piece of gemstone jewelry.

Color

The jewelry industry recognizes the highest quality gemstones by their blue, pink, green, or red hue, a medium to medium-dark tone, and saturated color. The best value is in colors that include "slight" traces of other colors, are not too light or dark, and have a lot of saturated color. Blue Nile offers some of the highest-quality colored gemstones available.

The beautiful color of a gemstone is its most defining characteristic, and many jewelers consider it to be the most important evaluation criterion. When deciding upon gemstone color, examine hue, tone, and saturation.

Hue

The most valuable gemstones are those that exhibit a pure color and only "slight" hues of other colors in addition to their primary color, as all Blue Nile gemstones do. Blue Nile blue sapphires range in hue from "slightly purplish-blue" to "slightly greenish-blue," pink sapphires always range from "pink" to "slightly purplish-pink," and rubies range from "slightly orangish-red" to "slightly purplish-red". If a Blue Nile gemstone has any variation in hue, it will be called out in the gemstone details on the product detail page.

Tone

Tone represents the depth of color, ranging from colorless to black. Gemstone tone is described as "light," "medium-light," "medium," "medium-dark," and "dark." Blue Nile offers gemstones with the most sought-after tones that fall within the medium-light to medium-dark range. For all of our gemstone jewelry, you'll find any tone variations are called out in the gemstone details.

Saturation

Saturation, or color purity, refers to the degree to which the gem is free from brown or gray hues. The most desirable gemstones, which show little gray or brown, are often described as having "vivid" or "strong" color saturation. You will not find levels of color saturation called out in the product details, because the gemstones in all our jewelry are chosen for their vivid blue and red color.

Clarity

Almost all gemstones contain tiny fractures called inclusions. Flawless gemstones are very rare and valuable, and even most high-end gemstones are at least slightly included. The best value is found in gems that are lightly- to moderately-included, like those found in Blue Nile gemstone jewelry.

Identifying marks

Because gemstones form under unique circumstances, each individual gemstone is comprised of a combination of trace minerals, which create a unique set of identifying marks or inclusions.

What to look for

Because sapphires are more commonly found in nature, those chosen to be set in jewelry often have higher clarity levels than rubies, but internally flawless sapphires are very rare. Because rubies are very rare, internally flawless rubies are extremely rare. Exceptional gemstones with few or no inclusions are available, but they command extravagant prices. For the best value, look for sapphires that are moderately included, and rubies that are heavily- to moderately-included.

Cut

Unlike diamonds, with gemstones you won't find an "ideal" cut geometrically configured for maximum brilliance. But a high-quality gemstone cut is one that presents the most even color, exposes the fewest inclusions, and displays the majority of the gemstone weight when set in jewelry.

To recognize quality in the cut of a gemstone, there are several points to consider.

What to look for

When choosing a sapphire or ruby, ensure that the gem doesn't display the bands of color common to corundum crystals, because if you can see these streaks, you can tell the gem was cut for maximum weight rather than beauty. The gemologists at Blue Nile review each gemstone in each piece of jewelry to ensure that the rubies and sapphires are cut to present consistent color.

Color saturation determines gemstone cut Greater color saturation requires a shallow cut Less color saturation requires a deeper cut Buyer's Tip In a gemstone with more saturated color, the best cut may be more shallow than average, permitting more light to penetrate the gemstone, while in a less saturated gem, the color may benefit from a deeper cut.

Gemstone Cut

Look at the gemstone in the setting and ensure that all the facets are symmetrical. An asymmetrically-cut crown indicates a gemstone of low-quality. In all cases, a well-cut gemstone is symmetrical and reflects light evenly across the surface, and the polish is smooth, without any nicks or scratches. These are the characteristics that Blue Nile jewelers look for when selecting our gemstone jewelry.

Elements of a step cut gemstone Buyer's Tip Like diamonds, fine quality color gems usually have a table, crown, girdle, pavilion, and culet.

Size

The carat weight of a gemstone is not necessarily an accurate gauge for gemstone size. To help you judge the size of a gemstone, Blue Nile lists the diameter of thegemstone when viewed from above — since if the gemstone is set in jewelry; this is the only part of the gemstone that is visible.

The carat weight of a gemstone does not necessarily allow you to accurately envision the size of the gemstone. Different gemstones have different densities (mass per unit volume), so two gems that appear to be the same size may actually have very different weights. For example, a ruby is more dense than a diamond, so a 1-carat ruby will look smaller than a 1-carat diamond of the same dimensions.

Gemstone dimension    Round 5mm Square 4mm  Over 4x6mm Pear 4x5mm Buyer's Tip Request the dimensions of a gemstone to ensure that the majority of the gemstone weight will be visible when set in the setting.

To help you envision the gemstone's actual appearance, we at Blue Nile provide the diameter dimensions (for round) or length and width (for other shapes) of a given gemstone. You can even click the zoom button to see a closer look at any piece of gemstone jewelry.

Enhancements

Nearly all gemstones available have been enhanced. Those gemstones that have not been enhanced are very recognizable by the extravagant price they command. Some enhancements, such as heating, are an expected part of the polishing and finishing process and are accepted by the jewelry industry, and by Blue Nile.

Looking at gemstones straight from the mine, they might be mistaken for pebbles or gravel.

Part of the process

Almost every ruby or sapphire you'll find has been heated, which is a practice that's been going on for centuries. Heating completes a process nature started, enhancing the gemstone to amazing colors of blue and red.

The jewelry industry recognizes heating as acceptable and expected processes. Heating is part of the polishing and finishing process for almost all rubies and sapphires. The heating of gemstones are practices accepted by the jewelry industry, the American Gem Trade Association (AGTA), and by Blue Nile.

For a more detailed understanding of heating practices, please read the AGTA's explanation of gemstone enhancements.

Care

Cleaning gemstone jewelry

After removing your gemstone jewelry, wipe it with a soft cloth to remove dirt and other residues.

To clean sapphires or rubies you can use either an ultrasonic cleaner, or a solution of one part ammonia and six parts water to clean your jewelry at home. If cleaning by hand, gentle scrubbing with a very soft brush should loosen most dirt and greatly increase the brilliance of the gemstone, but be careful not to scratch the metal of your setting.

Storing Gemstones

Store your gemstone jewelry in a case or a soft cloth, so the gems do not touch each other or parts of other jewelry. Gemstones are harder than gold, silver, or platinum and can scratch the surfaces of your other fine jewelry if they are not kept separate.

Wearing Gemstone Jewelry

Rubies and sapphires are second only to diamond in their ability to resist scratching, but since no gem is invulnerable, avoid abrasive substances and sharp blows, which can damage even the toughest gem.