Diamonds and gemstones have an interesting ability to create immediate opinions.
A stone comes out of an old jewelry box, catches the light, and somebody inevitably announces that it must be worth a fortune.
Maybe.
Maybe not.
As the owner of KenWorks in Metairie, Louisiana, I’ve learned that gemstones are very good at keeping secrets. Two stones can look almost identical across a countertop while being completely different materials with very different characteristics.
That is why gemologists evaluate stones rather than simply looking at them and making an educated guess.
There is science involved, specialized equipment, established grading standards and quite a bit of experience.
First, Figure Out What the Stone Actually Is
Before discussing quality or value, the first question is simple:
What is it?
- A clear stone is not automatically a diamond.
- A red stone is not automatically a ruby.
- A blue stone is not automatically a sapphire.
Jewelry contains natural gemstones, synthetic gemstones, laboratory-grown diamonds and a wide variety of imitation materials.
Some can look remarkably similar without testing.
Gemologists examine physical and optical properties to help identify a stone. Depending on the situation, that may involve magnification, measurements, refractive properties, fluorescence and other observations.
This is considerably more reliable than the traditional family identification method of, “Grandma always said it was real.”
Grandma may have been absolutely correct.
Grandma may also have been working with the information available in 1963.
Diamonds Have the Four Cs
Most people have heard about the Four Cs of diamonds: cut, color, clarity and carat weight.
Each describes something different.
Carat measures weight, not physical size.
That distinction surprises people sometimes. Two diamonds can have the same carat weight but look different in size because of their proportions.
- Color evaluates the amount of visible body color in many diamonds.
- Clarity deals with internal and external characteristics.
- Cut involves proportions, symmetry and polish, all of which affect the way light interacts with the diamond.
No single C tells the whole story.
A large diamond is not automatically more desirable than a smaller diamond. Size is simply one characteristic among several.
Magnification Changes Everything
One of the basic tools in gemstone evaluation is magnification.
A stone that appears completely clean to the naked eye may reveal an entirely different landscape under a loupe or microscope.
Gemologists may see inclusions inside the stone, surface abrasions, scratches, chips or other characteristics.
Inclusions are not necessarily bad.
Many natural gemstones contain them. In some circumstances, internal characteristics can even provide useful information about identity or formation.
The important questions involve what the inclusions are, where they are located and whether they affect appearance or durability.
Looking through magnification can sometimes feel like discovering an entire geological world inside something smaller than a pea.
Cut Is More Than Shape
People sometimes confuse cut with shape.
Round, oval, pear and emerald are shapes or cutting styles.
Cut quality goes deeper.
With diamonds, the angles and proportions of the facets influence how light travels through the stone and returns to the eye.
A diamond can have substantial carat weight but less effective proportions.
Colored gemstones introduce additional considerations.
A cutter working with ruby, sapphire or emerald may be balancing color, clarity and preservation of weight. Natural gemstone material is rarely a perfectly cooperative block waiting to become jewelry.
The original material helps determine what is possible.
Color Gets Complicated
Color is particularly important when evaluating many precious stones.
A sapphire is not simply blue.
A ruby is not simply red.
Gemologists may consider hue, tone and saturation when examining colored gemstones.
The distribution of color can matter too.
Some stones show fairly consistent color throughout. Others contain areas of different intensity.
Lighting conditions can also change perception, which is why gemstone evaluation should not depend entirely on how something looks underneath one particularly flattering jewelry-store light.
Those lights have one job, and they are very good at it.
Treatments Matter
Many gemstones undergo treatments.
Heat treatment, for example, has a long history in the gemstone trade. Other stones may be filled, dyed, irradiated or treated through different processes intended to change appearance.
Treatment does not automatically mean a gemstone is fake.
That distinction is important.
The question is whether a treatment exists, what type of treatment was used and how that information relates to the stone being evaluated.
Certain determinations may require advanced laboratory testing beyond a standard examination.
Mounted Stones Can Be Trickier
Many gemstones arrive for evaluation already mounted in jewelry.
That creates limitations.
Prongs can cover portions of a stone. A bezel may hide the edge. The setting can prevent direct weight measurement.
Gemologists can often take measurements and estimate certain characteristics, but evaluating a loose stone generally provides greater access than examining one inside a setting.
That does not mean Grandma’s ring needs to be immediately dismantled.
It simply means the setting has to be considered when interpreting the examination.
Condition Matters
Gemstones may be hard, but that does not make them indestructible.
Even diamonds can chip.
Other gemstones may develop scratches, abrasions or worn facet edges after years of use.
Older jewelry deserves particular attention because a ring worn regularly for 40 or 50 years has experienced quite a bit of life.
Condition becomes part of understanding the stone as it exists today.
Old Paperwork Is Helpful, but It Isn’t a Time Machine
Receipts, laboratory reports and old appraisals can provide useful information.
Bring them.
They may contain details about the stone, setting or previous evaluation.
But jewelry can change.
Stones can be replaced. Settings can be altered. Repairs can be made. Market conditions certainly change.
An appraisal from 1985 tells something about 1985. It does not automatically establish what an item represents today.
Gemology Replaces Guesswork With Information
The real purpose of gemstone evaluation is understanding what is actually there.
A diamond or precious stone may carry financial value, family history or both.
Sometimes the stone turns out to be exactly what the family believed.
Sometimes it doesn’t.
And every once in a while, something sitting unnoticed in a jewelry box for decades turns out to deserve a much closer look.
At KenWorks in Metairie, that discovery process is one of the interesting parts of working with diamonds and gemstones.
A little stone can contain a surprising amount of information.
The trick is knowing how to read it.