Pigeon blood ruby. Cornflower blue sapphire. Flame red spinel. The names conjure up great images in the mind of what these gems look like, but do we really know what their color is? Are these names a standard? Do they represent the same hue, tone, and saturation? They do not, and the differences in color, though slight, can be a difference of hundreds, or even thousands of dollars. And let’s not forget clarity and cut, for without high ratings in these categories, a fine gem would not be a fine gem.


History of Grading
We are decades into the age of technology, yet, we are infants in the communication of gemstone color and quality. Twenty five years ago, when I began publishing what is now the GemGuide, no standards for colored gems existed for either quality grading or color communication. We began as pioneers in a way. This was the first comprehensive industry price guide for colored gemstones and we needed a system. Our first book, published in 1982, had a limited number of colored gems with pricing grids similar but simpler than the ones in our current version. The quality grades we developed back then were good, fine, and extra fine.
Then, in 1985 (also the year diamonds became part of the publication), we expanded the quality grades to include a new grade of commercial. A numbering system from 1 to 10 was also introduced to associate these grades with a numerical quality rating. At this time, GIA was teaching color grading, and they introduced a color chart with a hue wheel and two other charts showing levels of tone and saturation. New grading charts appeared in their colored stone course to assist in quality ranking of color (more on this later). In our pricing publication, we used this information to assign a color grade of 1-10. This we followed with clarity and cut rankings, also on a 1-10 scale. A new formula was introduced to combine the color (50%), clarity (30%), and cut (20%) into a final overall grade and thus, our first grading system was born.

In 1990, another addition was made to the pricing charts for quality grading. Commercial was thought to be too wide a range for more expensive gems. To fine tune the pricing grids, we added grades of lower commercial, middle commercial, and upper commercial. Good and fine were also separated into lower and upper to aid in evaluation.
Twenty five years later, our quality grading terms have survived the test of time and we have not made any new changes to these grading terms. The four grades work and the corresponding number grades help to identify and rank these descriptive terms. Yet, we can hardly call it a standard. Part of the reason this is not a standard is because of the fear of what this would do to the colored stone industry profits like standardization did to the diamond industry. But overwhelmingly, the reason it is not a standard is because colored stones are highly subjective in nature. So, without a standard, dealers continue to create their own grades and we still see confusing terms such as AAA. Is AAA the best or can there be four or five A’s?

History of Color Communication

The GemDialogue system consists of these acetate sheets with each hue represented. Users will then take a black or brown overlay to show the mask.

Howard Rubin can be considered a pioneer in our industry with his invention named the GemDialogue. He was the first to raise our attention to the fact that we needed a better color communication system than meaningless terms such as pigeon’s blood. A standard for color communication already existed in our world, but not in our industry. Using the Munsell color system, Rubin adopted the principles to create the GemDialogue, which made its debut in 1983. His system consisted of acetate sheets of color hues that adequately give users the ability to match the color to a gem, and then describe it in terms of its hue, zone (his version of saturation), and mask (black or brown overlays that darken the color).
Around this same time, the GIA was using the color wheel as previously mentioned. It was simply a printed glossy page that was distributed as part of the color course. At one time, we even included these pages as part of The Guide through agreement with GIA. Within a few years, the GIA came out with a machine called the Color Master. This large, bulky, expensive instrument did not catch on at all and few were sold. It had its merits but with a price tag in the thousands of dollars, especially back then, it was destined for failure. Eventually it met its doom, but should be remembered for its first attempt at bringing technology to the color communication world.

Next came a flurry of color communication inventions, all of which promised to revolutionize the industry. GemScan was a product of the American Gemological Laboratory in New York, developed by C.R. “Cap” Beesley. He used a foil-like material viewed in oval cutouts on cardboard scales. Only a few sets were ever sold and he decided not to produce these commercially, so it could never become a standard. They used it only in their laboratory on their grading reports. The set became proprietary to AGL. They no longer use the color nomenclature from the GemScan cards on their reports. Now, they use a rating scale to describe the overall quality of the color. For example, a fine sapphire might receive a color grade of 3.5/85. The 3.5 is on a scale of 1-10 with 1 being the best so this would rank as Very Good. The 85 is the tone on a scale of 0 to 100. In this case, 85 would be classified as Medium-Dark.

Back in the late 1980's I can remember receiving several free prototypes of color systems for The Guide to review. None showed much promise. Another entry to the field was the World of Color book produced by Thom Tashey, then of the GQI laboratory, now named PGS in Chicago. The concept was good because he based the book on Munsell which was, and still is, a standard in the world of color outside of the gem industry. However, we in the gem industry like to believe that we are special and no one should tread into our arena. So, we try to create our own rules and our own standards. Lo and behold, the World of Color met its demise, too.

The GIA GemSet is no longer available. When it was in use, comparisons to stones were made to these plastic replicas on paddle-type holders with hue, tone and saturation notations.

Then, in the 1990's the GIA began selling a plastic set of simulated gemstone comparison pieces. Known as the GIA GemSet, this communication tool was originally developed by Ken Roberts. The set contained 324 individual pieces that represented the most common colors seen in the trade. More emphasis was placed on reds, greens, and blues, for obvious reasons. Each GemSet piece represented a combination of a hue, tone, and saturation. Because of the limited number of pieces, there were gaps–many gaps. The set sold for approximately $600. The company that produced the sets eventually required a minimum quantity order that was not feasible for our industry interest and with waning sales, the GIA decided to no longer carry this item.


Through all this, GemDialogue continued to stay the course. Rubin lectured often on color science and his grading tool and he continues to do so today. The GemDialogue is widely used and certainly has advantages of low cost and portability. We have always supported this system in our publication and continue to sell it on our website.

The opening screen of GemESquare shows the 31 hues around the square. From this, an initial hue is chosen. Here the bluish violet hue in the top row is selected, then the user will click on the "View Color" bar. See the next image.

The latest entry is the first serious technologically advanced communication system. We are hooked on computers and this system is all about computers. The GemEWizard is the collective name of all the products developed by Menahem Sevdermish. After years of development, the first version, the GemESquare, became available for purchase. Stuller took the first distribution rights with a limited exclusive start on selling the product for the first year. Now the GIA has adopted this and has exclusive marketing rights under the name of GIASquare. They have also committed to teaching the system in their classroom and to distribute a limited version to all students. Svedermish has stated that to date he has sold about 700 full working GemESquare units with 3,000 committed to the GIA students.

Note that we also carry this product on our website for purchase. The GIASquare starts by showing a square of the 31 standard hues. This replaces the old printed color wheel once included in their course. Once a hue is selected, that grid opens to show all possible color combinations of tones and saturation levels. As colors are chosen, they appear on the side of the screen so that comparisons can be made. Digital images can also be brought on screen to compare the actual gem to the colors on screen.

When the "View Color" bar is clicked, the full array of possible tones and saturations for that hue will appear on screen. As colors are selected from this screen, they will appear in the box on the left. Comparisons can also be made to selected images of gemstones.

The first criticism that jumps out and has been asked at every lecture that I have attended is the differences in color monitors. Any newer model LCD monitor is reasonably accurate. Those that wish to have the highest of accuracy can buy a device that color calibrates your monitor. Both sides have some validity to their arguments. If monitors do show even slight differences, this may be enough to make a difference on a fine ruby. For other gems such as amethyst, the differences are not as critical. Sevdermish states that he has done numerous tests with various monitors and with tradespeople, and the results are consistent for accurate color selection. Also, to combat the differences in color when photographing a gem, Svedermish has contracted with MK Photo to create a uniform lighting box for GemEWizard users. The box should be available by the Las Vegas trades show.

Our overall position is that any system under different conditions and with different graders will result in slight differences. These are tools to help describe and grade gems. I will take a GemDialogue color description of ‘R 70/40% gray’ or a GIA GemSet or GIASquare description of ‘Strongly purplish red, medium dark, strong saturation,’ any day over ‘pigeon’s blood red.’ The tools get us close and allow us to communicate. The eyes and experience do the rest.

Clarity Grading of Gems
The diamond grading scale first appeared in the industry in the early 1950's. The GIA openly encouraged its use and it soon became a standard. The familiar terms from Flawless down to I3 are now well-known and accepted world-wide.
When the GIA continued the ongoing development of gemology courses, they soon adopted these grades for colored gems. However, colored gems are radically different than diamonds and over the years, many in the industry were uncomfortable with these terms being used for colored gems. Note that while the GIA taught these clarity grades in their courses, they did not, and still do not, use clarity grading on colored gemstone reports from their Gem Trade Laboratory. Only diamond reports have quality ratings, whereas colored gems are identified only.

Some independent labs started their own colored grading systems. One such system was developed and promoted by the American Gemological Laboratory. Known for colored stone reports and country of origin determination, these familiar reports had a new grading scale for clarity. The grading scale for clarity was FI (Free of Inclusions), LI1 and LI2 (Lightly Included), MI1 and MI2 (Moderately Included), HI1 and HI2 (Highly Included), and EI1, EI2, and EI3 (Excessively Included). Other labs followed with their own in-house grading terms. However, none of these ever reached widespread acceptance.

As the GIA courses progressed, they realized that the diamond grading scale was unfair to some gems. For example, the trade and consumers alike accepted the fact that nature has always been unkind to emeralds and they typically grow with many flaws, often eye-visible. Rubies are also treasured gems and they grow with some degree of flaws, but usually not eye-visible. And there are gems such as aquamarine that are usually near flawless under magnification. It did not seem fair to grade all three of these gems with the same scrutiny putting most emeralds at the bottom of the scale.

Because emeralds typically have eye-visible inclusions, the clarity grading scale is more lenient. Emeralds are type classified as Type III. The grade for this would be moderately included.

So, the GIA developed a simple type classification system of Type I, Type II, and Type III. Gems that grow very clean in nature such as aquamarine, citrine, topaz, tanzanite, and chrome and green tourmaline are examples of Type I gemstones. Rubies, sapphires, rhodolite garnet, peridot, amethyst, spinel, and pink tourmaline are Type II. Emeralds and red tourmaline (rubellite) are Type III. Not all gems have been given a type classification by the GIA, only the more prominent gems at the time of developing the system. In 1984, these type classifications were added to The Guide as reference material that preceded the price grids. Each gemstone was then listed along with its type classification.

If a gem has not been type-classified, it is generally not difficult to estimate where it would fall based on experience. So, even though apatite has no classification, it often has cleavage present and some large stones may even have eye-visible inclusions. A classification of Type II would be reasonable.

In the 2002 course material from the GIA, new grading terms were also introduced to replace the diamond terms for colored gems. We heartily endorsed these. They are eye-clean, slightly included, moderately included, heavily included, and severely included. Charts in the course illustrate how to apply these grades based on the type classification.

Color, Clarity, Cut Combined
Now, it is time to put it all together. As mentioned earlier, our first grading system weighted the factors with color being 50%, clarity 30%, and cut 20%. Through the years, a better system was developed. Recognizing that color is still the primary factor in value (often augmented by superior cutting), we start with the color grade on our 1-10 scale. Next, the clarity grade is ranked. Based on the clarity grade a premium or deduction may occur. Finally, the cut is ranked and again a premium or deduction takes place. The chart shown here explains the factors that determine how much to add or subtract to get to the final grade.

The purpose of all this is of course to price gems better. Clearly we must all be talking the same language to do this with accuracy and consistency. The tools that are available today can help tremendously in this effort. Anyone who deals in color must have a communication tool that is reliable.

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