Emerald Guide

What is an Emerald?  Without becoming too scientific, emeralds are a variety of beryl.  Emeralds rate a 7.5-8 on the Mohs scale of mineral hardness, below that of rubies and sapphires (9 rating) and diamonds (10 rating).  Emeralds, as well as other gemstones like diamonds, rubies and sapphires, are graded on the 4Cs (color, clarity, cut and carat).

 
Emerald Color.  Emerald color quality is judged by hue (the emerald’s color), saturation (the strength or weakness of the color) and tone (the lightness or darkness of color).

The rarest and most valuable of emeralds will have strong, vivid color with as little blue-green or yellow-green elements as possible.  It should be remembered, however, that the rarest color emerald (a true, deep vivid green) is not necessarily the most valuable, as clarity, cut and carat size also play their parts in determining the value and cost of emerald jewelry.

Minute differences in one gemstone’s color over another are extremely important in rating the value of a gemstone from a gemologist’s point of view; however, for our purposes (and our purpose is to buy jewelry, right?), small differences in gemstone color may not even be discernible with the naked eye. 

For the average consumer, who is concerned with all the desirable elements of emerald jewelry – the stone size and color, the jewelry setting and the styling of the jewelry itself – these little differences are usually neither obvious nor of great concern. 

All other values being equal (cut, clarity and carat), you could well find that a beautiful bluish-green emerald appeals and suits you better than the most valuable of vivid green emeralds.  In the case of color, the best emerald color is that which suits you best.

Emerald Clarity Enhancement Treatments.  Emeralds are highly included gemstones, meaning that, by nature, they contain small internal flaws called inclusions.  This makes emerald jewelry much more prone to cracking and breaking than, say, diamond jewelry.  Emeralds are classified as a Type 3 colored gemstone by the GIA (Gemological Institute of America) which means it is a gemstone that almost always has inclusions present.

Because of the inclusions inherent in emerald jewelry, the majority of emeralds undergo some type of clarity enhancement treatment.  Traditionally this has been done by using an oil, usually cedar oil, to fill internal fissures in the emerald.  More recently, man-made epoxies and resins have been used to enhance an emerald’s clarity.  In any event, rest assured that clarity enhancement is an accepted, common practice for emeralds to undergo. 

Oil enhancement treatment is not permanent; the oil will dry out over time and your emerald jewelry will probably have to be taken to your jeweler’s for a re-treatment.  Both oil treatment and epoxy/resin treatment are particularly vulnerable to high temperatures, meaning your stone will need to be removed from its setting prior to any repair work that utilizes high temperatures.  Likewise, emerald jewelry should not be subjected to an ultrasonic cleaner or steam cleaning, which can remove emerald luster and weaken or remove the fissure-filling material used on the emerald.

For the purposes of judging emerald (or other Type 3 gemstone such as red tourmaline) clarity, the Gemological Institute of America uses a scale that ranges from VVS to I3:

VVS (Very, Very Slightly Included) – Inclusions easily identifiable under 10x magnification but usually not visible to the naked eye.

 VS (Very Slightly Included) – Obvious inclusions easily seen under 10x magnification, usually visible to the naked eye.

SI1 (Slightly Included 1) – Large and numerous inclusions under 10x magnification, prominent to the naked eye.

SI2 (Slightly Included 2) – Large and numerous inclusions under 10x magnification, very prominent to the naked eye.

I1 – (Included 1) – Inclusions very obvious, to the point of having a moderate negative affect on the gemstone’s appearance or durability.

I2 – (Included 2) – Inclusions very obvious with severe negative effect on the gemstone’s appearance or durability.

I3 – (Included 3) – Inclusions very obvious with severe negative effect on both the gemstone’s appearance and durability.

A couple of things worth pointing out:  Though GIA’s grading system for diamonds is by and large accepted as the standardized grading system, their colored gemstone grading system isn’t as widely adopted.  GIA, the AGTA (American Gem Trade Association) and AGL (American Gemological Laboratories) each have their own grading system for judging colored gemstones.

 
Emerald Jewelry Shopping Tips:

• Assume your emerald jewelry has undergone a clarity enhancement treatment (yes, it is THAT  prevalent), unless your emeralds come with a certificate indicating they are not clarity-enhanced.
• Be very aware of the included nature of emeralds.  While a pair of emerald earrings or an emerald brooch – both examples of jewelry that receives minimal wear and tear from routine use – can be a dandy idea, an emerald bracelet or emerald ring may be a dubious choice if the jewelry is going to be subjected to a lot of banging and bumping.  Remember, that emerald isn’t as tough as a diamond and it’s naturally prone to have little cracks and fissures to begin with – it might not fare so well knocking and bumping against hard surfaces.
• Natural emeralds versus lab-created emeralds:  Which is better?  Why not consider a lab-created emerald?  Lab-created emeralds, like other lab-created and synthetic gemstones are real gemstones, they’re just not natural gemstones.  They have all the chemical and physical properties of natural gemstones and only a trained gemologist is able to tell the difference between a natural gemstone and a lab-created/synthetic one.  You may find that a very, very slightly included lab-created gemstone is within your wallet’s reach, where a natural emerald of the same size, color and clarity, is not.
• An eye-pleasing alternative to emerald jewelry for those concerned with breakage is green tourmaline, a semi-precious stone that rates a 7-7.5  on the Mohs scale of mineral hardness, just a shade under that of the emerald, but without emerald’s inclusion-proneness and vulnerability to breakage.  And without emerald’s price tag.  The 'carousel' of jewelry that appears on the upper right side of this page is a mix of emerald and green tourmaline jewelry so you can do a comparison of the two gemstones.
• A quick internet search shows a 4.04 carat unmounted emerald cut green tourmaline, very very slightly included, selling for approximately $130.  The same vendor is selling a 4.42 unmounted emerald cut, oil-treated emerald, slightly included, for over $1,200.  Frankly, the tourmaline was more appealing visually.  Add greater eye-appeal to the fact that buying the tourmaline keeps about $1,000 in your pocket and tourmaline jewelry seems to be a favorable alternative.  Unless, that is, your heart is set on emeralds.  Then, of course, nothing else will do.