Buying a beautiful colored stone can be a frustrating task because there are no universally accepted grading standards for dealers to adhere to. It is not unusual to find one dealer touting a "nearly flawless" stone that looks exactly like the last dealer's "moderately included" stone.
In addition to this confusion with the clarity of a stone, how do you translate "daffodil yellow" or "sky blue", let alone "rich royal purple with hints of velvety blue"?
Then, you add the cut of the stone and you might as well throw up your hands in disbelief. As with clarity, there is no standard for cutting because each stone has its own refractive index which determines how the light will pay throughout the stone. This means that angles that will create an incredible looking tanzanite might create a lifeless looking amethyst.
The GIA, in its efforts to at least give some guidelines in colored stone grading and classification, have gone to great lengths to provide a workable system that is, at best, a good beginning.
Winfields believes there will never be a totally accurate system for describing colored gems. Even photography can not provide an accurate system to share the beauty of some colored stones, as the chemicals in the stone case light to react unfavorably when photographed, creating an unattractive looking stone that has great beauty when viewed by the unaided eye.
Some basic guidelines that will be useful when searching for a magnificent colored gem follows, but remember what Forest Gump says, "Beauty is as beauty does." You may look at all the certificates you desire, but buy the stone because it makes your heart sing.
Clarity Grading
For purposes of clarity grading, colored gems are divided into three categories by the GIA.
As can be seen, a type I colored stone VVS grade is eye clean, with inclusions that are difficult to see with 10x magnification and invisible to the unaided eye. While a type III VVS has inclusions that are easy to see under 10x magnfication and may have eye visible inclusions.
So, what's a poor rookie to do?
One thing is to understand the above scales and which stones are in each category. Do not be surprised if your local jeweler does not know each stone in the categories, or even what they are talking about when it comes to grading their stones.
If your local jeweler does not have at least a fair understanding of which stone should be normally eye clean, and which stones are still beautiful with a fair amount of eye visible inclusions, then it is probably time to locate yourself another jeweler who can help you to choose an amazing colored gem.
Colored gems is a specialist's game! Jewelers know all about diamonds and how the determine a quality one. They are the lifeblood of the industry, and therefore the most time is spent selling them. But, only a relatively few know and understand colored gemstones. Be sure you are working with one of those few if you want the best value for your money!
Quoting from the GIA workbook on Colored Gemstones:
"Color is an interplay between a light source, an object, and the human eye and brain. Most light sources emit light that is a combination (or blend) of various wavelengths of visible electromagnetic radiation. The object absorbs some wavelengths and transmits or relfects others to the eye. Receptors in the eye translate these wavelengths into an optical code which the optic nerve transmits to the brain, where they are interpreted as sensations of different colors."
Translation - Light hits the object we are viewing and is absorbed or reflected as different colors that the eye can see.
This is Important!
Some stones will completely different depending on whether they are seen in fluorescent light or incandescent light. ALWAYS look at a stone you are thinking of buying in several light situations. Get the jeweler to walk with you into a room with fluorescent lights, incandescent lights, and if possible, out of dors in shade and direct sun.
Back to the "book".
"We describe color in terms of three dimensions - hue, tone, and saturation. These create a world of colors or color space. All colors perceived by the human eye can be placed within this world, and their position specified by their hue, tone, and saturation."
"The color that is most important in a gemstone is called the dominant color. Other evident colors are called additional colors."
To paraphrase the rest of the description on color:
"Hue is the basic impression of color that we notice immediately. Red, green, and blue are some of the basic hue names. Add in other descriptors and you will get a better picture. For example, take the color wheel from the short journey between blue and green. Start with blue, then shift a little to very slightly greenish blue, and on around the wheel to greenish blue, very strongly greenish blue, green-blue or blue-green, very strongly bluish green, very slightly bluish green, and finally ending at green."
A similiar journey from green to yellow, yellow to orange, orange to red, red to purple, and finally from purple to blue can be seen on the color wheel as well. The human eye can actually discern about 150 separate hues, but gemology uses 31 on the hue chart. This serves for the vast majority of stones that will be seen in the jewelry world.
Tone
Tone is the lightness or darkness of a color sensation, from colorless to black. Tone is divided into eleven "steps" with 0 being colorless through ever increasing shades of grey until black is reached at step 10. When grading colored stones, seven of those steps are used, from 2 which is very light, through 8 which is very dark. The terms describe the lightness or darkness of the color the eye perceives.
Saturation
Saturation is the strength, purity, or intensity of the hue present in a color sensation.What we attempt to describe with saturation is how bright or how dull the color is. For example, a blue stone has seven grades of saturation starting with Neutral, but for practical purposes we use six modifiers for saturation, including grayish blue, slightly grayish blue, very slightly grayish blue, moderately strong blue, strong blue, vivid blue.
Blue is considered a cool color and cool colors are typically modified in shades of gray. Warm colors such as orange will typically be modified in shades of brown.
Putting it all Together
When you put it all together, you might get a color description of a really beautiful sapphire such as:
This sapphire has a medium dark, strong, violetish blue. Or in scientific color notation, vB 6/5 (violetish blue, medium dark, strong).
Why this is Important
If you take two jewelers, or even two colored gemstone shoppers, there will most likely be a wide variety of descriptors used when viewing a colored stone. This can be due to previous experience or classes taken to become a gemologist, equipment used to recreate the color descriptions, ability of the eye to see various colors, and a myriad of other factors.
Remember, no two people will see something in exactly the same way. This can lead to confusion, especially when dealing with a subject such as colored gemstones.
Cutting
Cutting colored stones is just as important, if not more so, then when cutting a diamond. Because of the various reflection patterns of different stones, it takes an expert to unleash the beauty of a particular piece. Cut right, the stone will SING! Cut poorly, it is just another window, perhaps with a little sparkle around the edges.
Buying an Heirloom Quality Colored Gemstone
The most important thing to buying a colored stone is to get out there and LOOK! View lots of stones, then look some more. It will quickly be seen that the vast majority of stones being shown are of "imperfect" quality. Ask to see well cut stones of high quality. Be prepared to go to several stores until you find one that can show you the type of stones that are worth purchasing. Save time by starting at some of the better local stores and putting off the "mall" shopping experience.
Winfields has an amazing display of colored gemstones and are able to get our hands on just about anything that your heart might desire. We are proud to feature the artistry of Richard Homer, one of the world's premier lapidary artists. When you see what he and others like him can do with stones, you will never be happy with native cut stones again.
Here are a couple of examples of a typical native stone cut versus what it looks like after re-cutting. Which would YOU prefer?
Finale
For the most part, take all of the above scientific "stuff" and enjoy reading it. Comprehend the parts of it that are important to you, then throw it all out and VOTE WITH YOUR EYES!
Colored gems are about BEAUTY! Buy the stone that makes your heart sing. If you can't find one, spend your money on something else!
