Criterion for Grading Colored Gems

"The colors of the rose and the violet are not less pleasing than those of the ruby and amethyst,

but the former endure but for a day while the latter can be handed down unimpaired from

generation to generation."

Oliver Cummings Farrington (1864-1934), Gems & Gem Minerals

In contrast with Diamond, which is classified using a very rigid grading system, no similar recognized classification system exists for colored gemstones.

One reason for this is the extraordinary variety that needs to be examined; color, transparency, brilliance, hardness and the multitude of different varieties are such diverse factors that reducing them to manageable categories becomes extremely difficult.

In order to distinguish between colored gemstones, experts have agreed to develop a general classification, based on which a precious gem is assigned an ‘A’, a superior quality gem an ‘AA’, and a truly excellent example an ‘AAA’.

Classification

Grading a colored gem requires more than solely evaluating the intensity of its color. Other criteria must also be considered, such as purity.

Interesting aspects

The Gemological Institute of America (GIA) classifies precious stones into three different groups based on the inclusions they contain:

  • Type I: These gems grow extremely clean in nature and usually have no eye-visible inclusions, for example Aquamarine, Citrine, Amethyst or Tanzanite.
  • Type II: These gems typically grow with some minor inclusions in nature that may be eye-visible, for example Ruby.
  • Type III: These gems typically grow with many inclusions in nature and they are usually eye-visible, for example Emerald.

An attempt to compare an Emerald (a type III gemstone) with a Tanzanite (a type I gemstone) and value them according to the same criteria is difficult. In fact, an AAA Emerald will certainly contain inclusions, but also excels in color intensity. The AAA Tanzanite offered by Juwelo is entirely pure, shows minor inclusions visible to the naked eye and has perfect Tanzanite coloring. Both, however, are the best examples of their variety, and thus given the ‘AAA’ label.

Juwelo AAA gemstones

An AAA rating in the gemstone world is not a protected quality mark; every jeweler is free to establish their own rating criteria. When selecting a gemstone, it is therefore best to allow your own careful assessment to guide you. You may have noticed that Juwelo has done away with the ‘A’ and ‘AA’ ratings. The ‘AAA’ grade is only applied to those examples that exceed the quality requirements for their own kind.

This means that you can rest assured by the quality offered with Juwelo's AAA gemstones .

A few examples of gemstones with different quality ratings

Different grades of a Nigerian Morganite: the example on the right is AAA Morganite.

Different grades of a Nigerian Morganite: the example on the right is AAA Morganite.

Different grades of Welo Opal: the example on the right is AAA Welo Opal.

Different grades of Welo Opal: the example on the right is AAA Welo Opal.

Different grades of Russian Emerald: the example on the right is AAA Russian Emerald.

Different grades of Russian Emerald: the example on the right is AAA Russian Emerald.

Different grades of Tanzanite: the example on the right is AAA Tanzanite.

Different grades of Tanzanite: the example on the right is AAA Tanzanite.