Grading Colored Gemstones Basics
Grading Colored Gemstones
How can you tell what quality a colored gemstone is? How are colored gemstones graded?
Like diamonds, there is a generally accepted system in grading colored gemstones. Although they are graded in terms of clarity and color like diamonds, that is where the similarity in grading systems ends. And generally, the consumer is not presented with grading information at the time of purchase.
Color is generally the most important factor in determining a gemstone’s value. Each type of gem has a range of color that is preferred. Gemstones that fall within this range have a higher value than those outside of it.
Clarity, a way of judging how free a gemstone is of internal and external imperfections (known as inclusions), is also considered when grading a gemstone. Clarity not only affects the appearance of a gemstone, it can affect its durability, depending on its size and location.
Cut is also an important factor. When comparing two gemstones, if the color, clarity, and size are similar, the one with the better cut will be worth more. The amount of “brilliance†a gemstone has reflects how good the cut is.
Even without formal training, most people can do a fairly good job of judging the color and cut of a colored gemstone. Does it catch your eye? Is it relatively free of inclusions (assuming it is a gemstone where inclusions are not expected)? How much brilliance does it have? Beauty is in the eye of the beholder to some extent, when considering cut and color.
Judging clarity, however, is different depending on the type of gemstone you are considering.
There are three clarity types in colored gemstones:
Type 1- These gemstones are expected to be “eye-cleanâ€. In other words, without magnification and upon a close inspection with the naked eye, it is difficult to see any flaws in the stone. Aquamarine and blue topaz are two Type I gemstones.
Type II – Minor eye-visible inclusions that do not detract from the gemstone’s appearance are expected in Type II gems and do not decrease the value, depending on the size and location. Sapphires and garnets are examples of Type II gemstones.
Type III – We expect these gemstones to have very visible inclusions and this does not necessarily detract from their value, taking into consideration the size and location of the inclusions, as well as the color and cut. Emerald and watermelon tourmaline are examples of Type III gemstones.
Visit us at Northwest Jewelry. If you have any questions about colored gemstones and how to grade them, I’ll be happy to help out.
SunstoneGal | 
March 16, 2007 10:39 pm