Some important points to know about colored gemstones

• Only 90 to 100 of the 3000 minerals are considered gemstones based upon rarity, durability, and beauty.
• Value of colored gemstones is far more dependent upon the quality of color as measured by hue (spectral sensation), tone (how light or dark the stone is) and saturation (how vivid to dull the stone is) then with diamonds.
• Cut is important in bringing out the best color and light return. Examine the colored stone for the amount of light that returns back to your eye compared to the amount of light that passes through the back of the stone (window) and dark areas (extinction)
• Clarity is important more for durability and optical quality. The less inclusion and cloudy appearance the better.
• Most color gemstones have some form of treatment (i.e. heat treatment) most are stable and do not affect the value adversely but some are unstable and might be done to deceive the buyer. It is advisable to ask if the stone has been treated and to deal only with someone who has the gemological training and experience to know the difference.

Natural vs. synthetic vs. simulant

• Natural gemstones have been formed in nature and fashioned and/or treated by man.
• Synthetic gemstones are created in the laboratory. They have the same physical, optical and chemical composition as their natural gemstone counterpart.
• Simulant is a gem material (natural or man made) that is used to look like a natural gemstone.
• Some gem materials are actually constructed of two or more substances. They are known as Assembled.