If you’re new to emeralds assessing if they’re a good price can seem a bit daunting.  And how do you know who you can trust?  Because of this we certify all emeralds we buy, using the 35 years experience of the independent Laboratory of Gemology RG (, based in the Emerald Centre in Bogota, Colombia, and pass that certificate on to you, free of charge.

We believe that the value of an emerald is only as good as the reliability of its certification.  Many sellers and shops do not have access to the skills or equipment needed to tell the difference between a $10,000 flawless natural stone and a $50 man-made stone.  You should always insist on proper certification.

This laboratory uses the standard  GIA (Gemological Institute of America, assessment and reporting standards and terms to help you chose the perfect emerald for you.  Here’s an explanation of those terms:

Emeralds are measured in units of carats, abbreviated as “ct” or “cts”.  Although it’s had different definitions in the past, since 1907 a metric carat has been equivalent to 200 mg (0.2 g; 0.007055 oz). Weight is typically recorded to 0.01 ct, but it’s doubtful if the accuracy of most commercial scales is significantly better than 0.05 ct. Emeralds vary in density though, so although they are priced by weight, when buying you should pay more attention to the size.

Emeralds are measured in millimeters, that is 11000 of a meter (5127 inch). They’re abbreviated as “mm”. Length, width, and height are typically recorded to 0.01 mm, but it’s doubtful if the accuracy of most commercial calipers is significantly better than 0.05 mm ( 120 mm,  5254 inch).

The most popular shape cuts are shown in the graphic. The signature “Emerald” cut is perhaps the most popular, and maybe shows off many stones at their best, but we think you should chose the shape you prefer for the jewelry you have in mind.

“Color” is really a catch-all term that means very little, though you’ll see plenty of sellers using it alone.  The GIA prefer to describe color in terms of hue, saturation, and tone (see diagram right).

Hue is the GIA name for what most of us regard as “color”: the colors of the rainbow, or the colors of a color wheel. Colored stones such as emeralds are classified by the GIA by specific names and abbreviations such as:

  • slyG: “slightly yellowish green”
  • vslbG: “very slightly bluish green”

The tone of a color is how light (white) or dark (black) it is. This doesn’t affect the stone’s hue but, as tone is intimately connected with saturation, this does change. Only a medium tone stone can have the very highest levels of saturation — lighter and darker stones are less strongly saturated.

Colored gemstone tones
Emerald tones

Saturation is the GIA name for the purity of the color of a stone: the narrower the range of a hue the stone has the more saturation it is said to have. Conversely, a stone which has a broader range in its hue would be described as “grayer” or “browner”.

All things being equal a stone with a vivid level of saturation will command a higher price than one which is moderately strong. But stones which are lighter or darker in tone simply cannot have higher levels of saturation so don’t bother looking for vivid saturation in that beautiful light apple-green stone you’ve set your heart on.

Colored gemstone saturation

The GIA classify emeralds as a “Type III” gemstone, almost always having a high level of inclusions (fissures, gas pockets, liquid, even other minerals).  Micro-photographs of these can be seen here. It is rare to find an emerald free of visible inclusions, and even rarer to find a large one, so large, clean emeralds can command prices in excess of diamonds.

gia clarity text

Whilst some dealers classify the clarity of emeralds in the same way as a colorless, Type I, stone such as a diamond (FL, IF, VVS1, VVS2, VS1, VS2, SI1, SI2, I1, I2, I3) the GIA recommend that Type III stones such as emeralds are classified using the scale:

  • Eye-clean: appears clean to the unaided eye.
  • Slightly included: noticeable inclusions apparent to the unaided eye.
  • Moderately included: obvious inclusions very apparent to the unaided eye.
  • Heavily included: prominent inclusions that have a negative effect on appearance or durability.
  • Severely included: prominent inclusions that have a severe effect on appearance or durability, or both.

In reality, perfection of a colorless stone is much more important than that of a colored gemstone such as an emerald. That’s not to say that clarity does not play a part in its valuation, it clearly does, but that eye-clean or slightly included stones are perfectly acceptable for fine jewelry applications.

Inclusions in gemstones, such as fissures, that reach the surface of the stone are routinely treated with colorless oils, resins, or similar products in order to improve its visual appearance. This is perfectly normal and permitted as long as it is declared.

The GIA classifies the levels of enhancement as:

  • None/Insignificant
  • Minor
  • Moderate
  • Significant

The level of enhancement possible is related to both how many fissures reach the surface, and just how many fissures there are in the first place: clearly a stone with few fissures can have little enhancement done to it.

Enhancement categories
CDEV Emerald Clarity-enhancement Classifications chart
Gemstone valuation

Unlike many dealers we deal only in independently-certified emeralds so you can choose with the confidence that what you read about our stones is not our opinion but that of a certification laboratory with over 35 years of experience and reputation.

When it comes to choosing a gemstone you should be guided first by the color and shape that you want for your jewelry. Although certain shapes/colors/tones are considered “better”, and therefore are more expensive, you should focus on what makes you happy.

But, if you seek classical emerald quality for that once in a lifetime purchase, and yet feel overwhelmed by everything you need to learn to assess an emerald, we’re here to help.  We combine all the quality factors  — color (hue, saturation, and tone), clarity, and enhancement into a single rating: Our opinion:

  • Good: A perfectly good gemstone at a great price.  You won’t be disappointed with this, we promise.
  • Better: Just what it says on the tin: A better quality gemstone if you’re able to pay a bit more.
  • Best: Our best emeralds: With superior levels of color and/or clarity these will really stand out.
  • Wow!: A superlative product combining the best levels of all color factors, exceptional clarity, and beautiful cutting. We don’t always have these in stock, and reserve this classification for the few stones we find that both have great certification and have a fire about them that make us go “Wow!”.

Armed with this rating all you have to do is chose the shape/cut you prefer, and the size/weight you want and we’ll rush it to your door.