Of all the different emerald sources in the world, the greatest amount of high-quality emeralds comes from Colombia. Colombian emeralds also make up around 90% of all emeralds in the gem trade, with the remaining 10% split between Zambia and Brazil.
High quality emeralds do come from sources other than Colombia, with one emerald vendor I know preferring Zambian emeralds over the Colombian ones in most cases. There are always exceptions to these generalizations due to nature never making two things exactly the same way.
One of my personal favorites, from the same vendor’s entire to-date collection, is this Colombian emerald (E1557). It has not been treated, and its color shows exceptionally well even if it is a little light for an emerald. Lighter stones typically look brighter after being placed in a setting, since the setting reduces the amount of light reaching the gem.
E1557 | right | medium | play
Emerald ID: E1557 – Weight: 0.83 Carats – Origin: Colombia – Treatment: none
E1496 | play |medium | left | “Emerald ID: E1496 – Weight: 0.56 Carats – Origin: Colombia – Treatment: None” A very important factor that many vendors forget to mention with emeralds is their treatment status. Emerald vendors know that more than 99% of emeralds are treated for clarity (usually oiled with a high-viscosity cedar oil). They buy and sell these emeralds under the assumption that a treatment has been made to them (specifically for clarity). The lack of disclosure for treatments between retailers and buyers caused a big scandal decades ago that made the gem industry much more keenly aware of the importance of educating customers. Unlike the previous example, most emeralds look more like this before treatments. Sometimes they appear nearly opaque.
Scandals aside, untreated emeralds are very rare. This makes the remaining ones exponentially more expensive than their treated counterparts. The larger the gem, the more the price is multiplied. The Rockefeller Emerald is considered to be one of the most perfect emeralds in the world as well as one of the most expensive at $5.5 million, though it is not the largest. Even the Natural Emerald Company (NEC) has similarly sized gems.
Rockefeller Emerald –
Weight: 18.04 Carats – Price: $5,500,000
Emerald ID: E1173 – Weight: 14.02 Carats –
Origin: Colombia – Treatment: Oiled –
However, the prices are not even remotely comparable. This is for two reasons: Having the Rockefeller name attached to the emerald gives it a lot of value that no amount of quality could create. Second, the sheer quality for the size of the gem. There is not only a lack of treatment, but a lack of inclusions making the gem eye-clean. This is crazy for emeralds as a gem that is bought and sold on the assumption that it is heavily included and has been treated.
The 4Cs of color, clarity, cut, and carat weight also come into play for emeralds, just like any other gemstone. Color is evaluated based on hue, tone, and saturation for emeralds, which falls into a very narrow range. Emeralds are often vividly saturated, and only certain colors are called emerald instead of green beryl (with emeralds being a type of beryl). Clarity is another range, though emeralds are always expected to be visibly included. Cut is determined by the skill of the cutter, as well as the shape of the uncut gem. Carat weight is taken into account after cutting, and acts as a rarity gauge to the previous three Cs.