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Guide to Gemstones

Guide to Gemstones
Kseniya Burns

Gemstone jewelry was always in style. Some stones are more thought after than others, however, each and every one offers unique possibilities. Gemstones have been used in fine jewelry as well as fashion accessories for centuries. Pearls have been used as buttons, rubies, sapphires, and diamonds graced crowns of kings and queens as well as their regalia.

Today you can find precious and semi-precious gems in jewelry, high end purses, and watches among many other things.

Diamonds are not the only option for valuable, heirloom jewelry. Sapphires, topaz, zircon, aquamarine, and emeralds are highly prized gemstones that can add value and style to your collection. Below are some of the most important factors that go into judging the quality of a gemstone.

Semi-Precious & Precious Gemstones

In order to earn the title of a precious gem, the stone must be rare and hard to find. There are only three precious colored gemstones: ruby, sapphire, and emerald. These stones are rarely found in their pristine form which is why some imperfection in color and clarity is acceptable.

Semi-precious gemstones include all other gems. Semi-precious gemstone prices vary widely depending on the availability of the stone and the ease with which it can be mined and processed, the color, and clarity. Because there are more semi-precious gemstones than there are precious gemstones, the color and clarity standards to which they are held are higher.


The highest quality gemstones are recognized by their hue, saturation, and tone. The best and highly valued gemstones have a light or no hue, have a great saturation of color, and are not too light or too dark.


The most valuable gemstones are those that only have a slight presence of other hue in their color. Some hues are more preferable than others, some are rare, and some are more budget friendly. The GIA uses a 31 color system to describe primary color of the gemstone. The comparison use to be done with a set of swatch cards that were compared with each stone. Today, jewelers use sophisticated technology for a better assessment of color.


Saturation is a purity (intensity) of a hue. The higher the saturation, the higher the saturation scale the gemstone appears. The saturation scale goes from 1 to 6. Gemstones with a score of 1-3 will have a brown or gray modifier to them (brown for warm color stones, gray for cold color stones), 4-6 will be the highest saturation of color without any modifiers. Gemstones that fall into that category are said to have “vivid” or “strong” color saturation.


Tone refers to how light or how dark the stone is. According to GIA there are 10 degrees of tone that range from 0 (colorless) to 10 (black). Rating of 0 is basically non existent. Most gemstones fall into the range between 2 to 8.


Clarity refers to the apparent degree of inclusions (flaws) in the stone. Almost all of the gemstones have inclusions. Clarity of a gemstone is dependent to the degree to which these inclusions are visible and where they are located. Gems with minimal amounts of inclusions are usually higher priced. In some cases inclusions will dictate the cut of the gemstone. Jewelers go to great length to hide imperfections in the stone so they are invisible to the naked eye.


Gemstones are generally cut to maximize their color and to obstruct inclusions. However, in the case of some rare and especially valuable gemstones the cut is determined by the desired total weight without any consideration for color or clarity. In these cases the gemstones will display some striations and possibly different hues.

Gemstones that have more vivid color may benefit from a shallower cut in order. Those with less vivid colors benefit from a deeper cut that accents the color. The perfect gemstone will have a perfectly symmetrical cut without any surface imperfections.


Nearly every gemstone that you touch today have been through some sort of an enhancement process in order to maximize the attributes of the stone. Gems that haven’t been enhanced are extremely rare and very expansive.

There are number of way through which a gemstone can be enhanced. Some of the techniques used date back centuries, others are more recent. Below is the list of the most common techniques used to maximize the attributes of colored gemstones.

Heat treatment

During this process heat is applied to a gemstone to enhance its color and clarity. This is a common practice around the world and has been used for centuries. Heat treatment is accepted by the AGTA (American Gem Trade Association).


Is a process during which a gemstone is injected with resin, glass, wax, or other materials to maximize clarity and color of a stone. This is another practice that is still used today.


During this process a coating of wax, oil, or other synthetic substances is applied the exterior of the stone. This practice is very common with porous gemstones. Coating porous gemstones enhances their natural color and improves durability.


This is a common technique used in the treatment of white pearls. Gemstones are bleached through the application of various chemicals and other substances to lighten the stone and enhance color.


A technique where color agents are added to the stone in order to enhance or change the color.


During this process radiation is used to alter the color of the stone. Irradiation is usually followed by a heat treatment to permanently stabilize the color.

Basic Gemstone Care:

Although gemstones are durable and can withstand daily wear, some require more care than others. Many gemstones are highly sensitive to household cleaners, cosmetics, and temperature changes. Follow these guidelines to ensure long and lustrous life of your gemstone jewelry.


Many gemstones cannot be cleaned using traditional jewelry cleaning methods. We recommend that you take your gemstone jewelry to a professional to get it cleaned. If, however you decide to d it yourself, follow the following guidelines:

  • Use non-abrasive jewelry cleaner.

  • Always read the labels on the jewelry cleaner. Make sure that your specific gemstone can be cleaned using the product.

  • Use a soft, non-abrasive cloth to clean your gemstones.

  • Soft gemstones such as amber, pearls, and coral should never be soaked. Instead simply use a soft cloth to wipe the surface of the stone.

  • Never use toothpaste or other abrasive chemicals to clean your gemstones. If you are unsure of what you should use in order to clean your gems, ask a jeweler for help.


  • Always store your gemstones in a lined case not touching each other or other jewelry. Some gemstones are durable enough to be scratch resistant, however, those gems can scratch settings of other jewelry pieces.

  • Make sure that you store your gemstones out of direct sunlight and heat. Certain gems can fade when exposed to sunlight for prolonged periods of time.


  • Although most gemstone jewelry is made to wear every day, even the most durable stones such as diamonds, rubies, and sapphires can cleave if they are hit at just the right angle. Avoid striking, scratching, and hitting your gemstone jewelry as much as possible to insure that your piece remains damage free.

  • Try to avoid swimming in your gemstone jewelry as saltwater and chlorine can negatively impact the color of your stone.

  • Always put on your jewelry last when getting ready. Perfumes, cosmetics, and hairspray can damage the stone.

  • Try to avoid coming in contact with petroleum based cleaners and other household chemicals. This is especially important if you are wearing pearls, coral, amber or other soft, porous gemstones. Petroleum based chemicals can melt and discolor some gemstones.