Colored Gemstone Clarity Scale
The gemstone clarity scale was created specifically for grading diamonds, more specifically, white diamonds -- not colored gemstones. For colored gemstones, it is difficult to use a 'one size fits all' classification system for clarity, since some colored gemstones are expected to have inclusions and are sometimes even identified by their inclusions. For example, the inclusions of emerald often provide evidence that it is natural. Additionally, some inclusions are desirable, such as 'horsetail inclusions' in demantoid garnet and rutile 'silk' in sapphire.
The colored gemstone clarity scale depends on the type of gemstone. Since colored gemstones vary so greatly, GIA (Gemological Institute of America) classifies colored gemstones as either 'Type 1', 'Type 2' or 'Type 3'.
Type 1 gemstones include beryl gems, such as aquamarine, heliodor (golden precious beryl) and morganite; yellow and green chrysoberyl, pale color amethyst, citrine, smoky quartz, spodumene, tanzanite and blue zircon. These stones are usually 'eye clean', meaning that no visible inclusions can be seen with the naked eye. Type I gemstones with visible inclusions are rarely used for jewelry, unless set in a mounting that conceals the flaws.
Type 2 gemstones include amethyst, ametrine, andalusite, alexandrite, citrine, corundum (all sapphire and ruby), garnet, iolite, peridot, spinel, tourmaline that is not green, pink or watermelon, and zircon that is not blue. These stones are usually included, which means that some eye clean stones can be found, but in lesser amounts than type 1 stones. Type II gemtones with minor inclusions visible to the unaided eye are very often used for jewelry; these include sapphire and ruby.
Type 3 gemstones includes gems such as green emerald, red beryl (bixbite) and varieties of tourmaline, particular blue tourmaline (Pariaba tourmaline and Indicolite tourmaline) red (rubellite) tourmaline, as well as pink, bi-color tourmaline and multi-color or watermelon tourmaline. For a type 3 gemstone, an IF clarity rating is incredibly rare, since these stones are almost always included. For type III gemstones, even those with very noticeable inclusions are often used for jewelry, such as the case with emerald and watermelon tourmaline.
- First Published: April-04-2006
- Last Updated: September-23-2016
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