Semi Precious Stone Beads » Gem Stones Buyers Guide

The sparkle and historical significance of semi precious gem stones is unmatched. They are available in diverse varieties and hues. Before making a purchase, a basic understanding of the value of gems is essential. Regardless of the gem variety, there are a few constant rules to be kept in mind while selecting the gems. Owing to the different types of natural, synthetic and imitation stones in every color, shape and size, it is necessary to get acquainted with the specific semi precious gem stones. The prices are guided by the desirability, quality and availability of gemstones.

Color
The color is the most defining factor when evaluating the colored gems. It is important to look at the hues, tone and saturation, when deciding upon a gemstone color. The more attractive the color, the higher is the value. The highest quality gemstones have a pure color and posses very slight shades of other colors. Tone represents the depth of the color, which can range from colorless to black. The tone of a gemstone is described as “light”, “medium-light”, “medium”, “medium-dark”, and “dark”. Bright, rich and intense colors are valued over those that are too dark or light. Colors that are dulled by tones of black, gray or brown are regarded as less desirable. The particular colors and shades of the gems affect the prices of gems that is also affected by the personal preferences as well.

Optical Effects
The brilliant colors displayed by some specific gemstones are optical effects caused when white light is split into its constituent colors. Some gems exhibit unusual optical effects known as phenomena that rare and beautiful and add immense value to the gems. The Cat’s Eye Effect, the Star Effect and the Color Change Effect are very popular phenomena.

Chatoyancy
Chatoyancy or the Cat’s Eye Effect is a reflection effect appearing as a single bright band of light across the gemstone's surface. It is generally found in Chrysoberyl, Tourmaline and Tigers Eye.

Asterism
Asterism or the Star Effect appears as two or more intersecting bands of light across the gem's surface. The phenomenon is commonly found in Ruby, Sapphire and Garnet.

Color Change
Color change gems have the capacity to distinctly change their regular color when viewed under two different light sources. The phenomenon commonly in Alexandrite, Sapphire and Color Change Garnet.

Iridescence
Iridescence refers to the rainbow like color effects as seen in some specific gems. It is generally found in Opal, Ammonite and Moonstone.

Aventurescence
Aventurescent gems posses colorful play of glittering reflections from small metallic inclusions. The phenomenon is common in Sunstone, Aventurine Quartz and Gold Stone.

Cut & Polish
The process of cutting and polishing gems is called lapidary. A well-cut gemstone is symmetrical and reflects light evenly across the surface and the polish of the stone is smooth without any nicks. Owing to the variable optical properties of colored gems, the cuts are determined by the color saturation. There is no ideal cut for gemstones that is geometrically configured for brilliance like diamonds. A greater color saturation requires a shallow cut, while less color saturation requires a deeper cut. A well-cut colored gem has even color, good brilliance, minimum number of inclusions and a good symmetry and polish conditions. Facets need to be aligned straight in relation to the gem’s girdle and also to each other. While choosing a gemstone, the polish must be flawless with no visible surface pits and polishing lines.

The gem cutting styles are divided into:
Faceted Gems- Those gems that have geometrically shaped flat polished faces
Non-Faceted Gems- Those gems that do not have geometrically shaped flat polished faces such as cabochons

Carat Weight
Gemstone carat weight refers to its weight. Gems vary in density and weight and not all gemstones look the same in size. This unit of measurement originates from the traditional use of carob seeds to weigh gems. Carob seeds were used because of their consistent size and shapes. One carat is equivalent to 0.20 Grams that is further divided into 100 smaller units known as Points. As the weight of a gemstone increases, its price also increases.

Clarity
Each individual gemstone comprises of a combination of trace minerals that create identifying marks or inclusions in the gemstone itself. The tiny natural features are most easily glimpsed under magnification. For desired effects, inclusions need to interfere with the brilliance, sparkle and fire of a gem. The best value is found in gems that are lightly to moderately included. The clarity of gems is determined by judging the amount and location of inclusions seen. The higher the clarity grade, the higher is the value of the gem.

Gems that have greater durability and resistance to wear are more highly priced than those of lesser durability.

Rarity
Generally, rare gems are more highly prized than more common varieties. However, if a gem variety is so rare that it is essentially unknown to the general public, it is often classified as a "collector gem". Gems such as Boracite, Childrenite and Simpsonite are extremely rare, attractive and durable, but they are unlikely to command prices appropriate to their rarity because fewer people are aware of their existence.

Historical Connotations
The quality gems rich in history and lore have high prices than the ones lacking a rich lore or history. The variety of Ruby from “Mogok Valley in Burma” is exclusive and paid for more than the Ruby from elsewhere.

Gemstone Treatments
The gemstones are often treated to improve their appearance. Some of these treatments are permanent while others are not. Diffusion deepens the color of the gemstone, but only within its outer layers. Oil and waxes are used to fill-in surface-breaking fractures. Treated gems can be a good choice to pay a price that reflects a stone's true quality.