Because colors occur in a mixed state in gemstones, we must first understand a little about both color theory and color mixing. This understanding represents the first step in a process we have decided to call sensitization. In order to understand and comprehend color we must be sensitive to it physically and be able to describe what we see. The ability to describe color will come to us by establishing a lexicon of colors as applied to gemstones. People need words on which to hang their perceptions. This is especially true of subtle experiences found in gems such as color variation, mixing, and overtones. Without a proper set of words, we cannot discuss with other people what it is we see. Without the words our eyes tend to dismiss what our eyes try to tell us. You will be surprised to see how slow and tentative people are when you show them a stone and ask its color, especially if they know you do not mean the obvious predominant color and are really trying to pin them down. You would think 90% of population was color blind. Since most people are not schooled in color so they are in loss for proper words to use, which in turn makes them unsure of what they see and what to say. Further, this lack of education seems to breed a difference of opinion in what they see differently. It can take a group of serious minded adults five or ten minutes to decide the color of a given stone.
We find a different group of people in the fraternity of gem dealers. In order to survive at the dealer level a person has to become sensitive to color. A dealer who lacks color sensitivity would go broke in a big hurry. He would be unable to know a good buy from a bad buy, would almost certainly pay too much for his merchandise, and be unable to know his customers’ needs. There are other problems he might have, but these three may alone are enough to pave the road to the poorhouse. In contrast, the dealer who has natural sensitivity to color cuts his learning time to the minimum, avoids a few bad buys and generally becomes prosperous more quickly than his peers. The preponderance of these dealers falls between these two extremes. They learn at an average pace and after some time in trade become quite color sensitive.
All of the grading system for colored stones are relatively new and most of them could be classified as experimental. As yet the jury is still out as to which system is the best and which system will prevail as time goes on. However, it is our opinion that the GIA system will inevitably become the industry standard. The obvious reason for that are several years of research and thousands of man-hours of time that went into formulating the system. The fact that the GIA is a nono-profit institution with third party impartiality is another reason. Another not so obvious reason. in our opinion, will be the fact that their system is open to every interested person and not guarded for their use only. All persons interested in colored stones need access to a viable, well-accepted system.
IN THE MEAN TIME
While you may presently not have the time to take one of the GIA’s courses you still need to become familiar with color as it relates to gemstones. The following few pages give some basic information that will help you understand color in gems.
Additional problems arise because nature virtually never makes pure colors – a point made by most art teachers. Since the crystalline materials fashioned into gems are made by nature, they seldom are pure in color. When we attempt to evaluate the color of a gem, our attempted description tries to tell some very subtle properties of the gem. By comparison, when we describe the clarity of a stone we can say it contains no inclusions or we can say it has inclusions. However, if we were to try to describe the clarity of an included stone with the same precision with which we try to describe color, we find variations in the attempt to describe clarity. For instance, a long inclusion might variously be described as needle-like, tubular, rod-like, cylindrical, or threadlike. Such accuracy of description does not matter with inclusions but does matter with color. The existence or non-existence of inclusions and their general size is all that matters with inclusions. But, with color the subtle differences we see make huge amounts of dollar differences. Color is the single most important factor in the four “C’s”. Subtle color differences equivalent to distinguishing between rod-like or thread-like inclusions do make dollar differences and are recognized in the trade. When we ask what is the color of a given gem we can seldom answer red, green, blue, or yellow, and be accurate. Realistically, we are asking what are the colors in a gem; which is the most predominant and by how much. The predominant color of a given stone may be red, blue, or green (a mixed color itself), but there are always primary and secondary overtones present which affect the price more than any other factor in stone evaluation.