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Lab Magnifying
Gauging the Quality of Emeralds - Several Important Guidelines
Emeralds, the most famous of the green gems have been sought after and coveted for thousands of years. Since the times of the ancient Pharaohs up to the present the allure of emeralds has captured the minds and hearts of man. Yet not all emeralds are equal, there are certain characteristics that differentiate quality emeralds from less desirable stones. Whether comparing to purchase an emerald or just browsing them, these five basic guidelines will help anyone gauge the quality of emeralds.
Before we cover the list of guidelines, first lets take a look at what emeralds are. Emeralds are a rare form of the mineral beryl, but they are not alone in the beryl family. The name beryl applies to several varieties of gems all with similar chemical compositions. The word beryl stems from the Greek 'beryllos' which translates 'precious blue-green color'. Even so, not all beryls have this characteristic. Aquamarine is perhaps the closest of the beryls to emeralds being a very light bluish-green color resembling that of clear deep water, hence its name. The red form of beryl is known as bixbite. While goshenite is the clear form of beryl. There is also heliodor and morganite which are yellow and pink respectively. The colors of beryls vary due to slight differences in elemental influences. Each of these beryls are unique, and like emeralds have different standards and levels of quality. With that said, lets examine what sets emeralds apart and how to gauge their quality
Observe the Color
The first and most important characteristic to gauging the quality of emeralds is color. Colombia has been famous for emeralds of exquisite beauty since the mid 1500′s. The mines at Muzo and Chivor are the most noted in trade circles and sometimes this can be misleading. Emerald traders will often use the names Muzo and Chivor in describing the color of an emerald when in fact that may not be the origin. As a general rule Muzo implies a grassy green, yellow being the secondary color. Whereas Chivor represents a deep pine green, blue being the secondary color. Similarly with Brazilian emeralds, the name implies the color more so than the emerald mine or country. None the less,value lies in the color more so than the origin. "Beauty is in the eye of the beholder" emeralds are rare, as are all gemstones. However, emeralds being even rarer than diamonds, make both the Muzo and Chivor type emeralds highly prized and often quite expensive.
Judge the Clarity
A close second to color in determining the quality of emeralds is clarity. The more opaque an emerald the less it is worth. Emeralds are the most included of all the precious gemstones, which to some degree effects their clarity and certainly their value. A nice emerald will have what is known as eye clarity, which basically means no highly visible fissures or cracks. It will have a smooth silky appearance and light will sparkle with fire throughout the stone. However, a quality emerald will have loupe clarity as well. A loupe is what is referred to as a jewelers magnifying glass. The standard loupe is 10x and less than that is not recommended, as extremely fine cracks extending the entire width of the stone may not be seen. All emeralds are treated with special oils to reduce the visibility of inclusions. When purchasing an emerald check the clarity with a loupe if possible, if not be sure you purchase from a reputable company. One sure way to tell if a company reputable is by checking their record of customer satisfaction as well as their return policy. On a side note: Beware of composite emeralds, these are emeralds that are pieced together from fragments and are held together with special bonding agents, a loupe will easily distinguish them from real emeralds and reputable dealers and jewelers alike loath them.
Notice the Cut
When most people envision emeralds the classic emerald cut comes to mind, and for good reasons. The step cuts and symmetry of the classic emerald cut allow for maximum light reflection and refraction. That is not to say other cuts are less valuable by any means. When it comes to cut, precision determines value. For example, if a sparkling radiance is not visible the cut could be too steep allowing light to escape from the sides causing a pale look. On the other hand, too shallow a cut and the emerald will appear dark and dull. Because of inclusions some emeralds have to be cut a certain way, be it pear-shaped, heart-shaped, tear-shaped or diamond cut. This is done to minimize the loss of raw crystal during the cutting process. A precision cut no matter the shape will only increase the value of the emerald.
Carat Weight
The least important on the scale in gauging the quality of emeralds is carat weight. That is not to say weight is not significant. Of course a highly clear deep green emerald weighing 5 carats would be worth far more than a 2 carat emerald with exactly the same qualities. However, a 1 carat emerald could be worth much more than a 4 carat emerald of inferior color and clarity. Unlike diamonds where weight is focal, emeralds should always be gauged by color and clarity first followed by cut and lastly weight.
Synthetic Vs Natural
A common misconception is that synthetic (lab grown) emeralds are fake. The fact is they are real beryl and are emeralds. The difference is they are man-made, not naturally occurring. Synthetic emeralds have telltale signatures in their inclusions that gemologists can easily recognize. The earliest attempts at growing emeralds in the lab failed due to their extreme clarity. The lack of inclusions were their demise. However, modern technology and highly sophisticated equipment have been able to duplicate inclusions in lab grown emeralds. Partially because of this FTC law requires jewelers to disclose the properties of emeralds they market if they are synthetic. All reputable dealers and jewelers subscribe to this policy as it protects the market investor as well as the dealer. With that said, it's important to note, although not worth as much as natural gems, lab grown emeralds are still quite valuable for the same reasons naturally occurring emeralds are.
When setting out to buy or browse emeralds, be it at a gem show, a jewelry shop or online. Following the five guidelines above will not only aid you in gauging the quality of emeralds, but help you gain the respect of reputable jewelers and dealers as well protect your interest.
About the Author
Wesley Ivins is an emerald enthusiast who maintains the website Emeralds are Forever a WordPress blog dedicated to emeralds. To learn more about emeralds visit http://emeraldsarerforever.com/
1 basic physics question?
What is the average of the 3 values for the focal length to get a single value?
I'm doing a lab where I have to locate the focal length of a magnifying glass. I am using these lens to project an image of a candle flame onto paper.
What is the focal length for the FIRST object location?
I lit the candle and put it on the table.
I held my lens 3 feet from the candle.
I held the paper on the other side of the lens from the paper & moved it toward & away from the lens to locate the image.
The image looks like an upside-down candle flame. The image is clear.
I moved the candle to 2 more locations from the lens and repeated the process.
I moved the candle at least 15 cm (6 in) each time.
I used the object & image distances to calculate the focal length of the lens.
The same as any average!
Add the values and divide by the number of values added.
In physics you can only add values with the same engineering unit.
In physics engineering units must be included in your math.
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