Natural Emerald Grading
Color is the number one thing that determines the quality of natural emeralds. In regards to natural emeralds, color is divided into three categories which include hue, tonal grade, and saturation. Tonal grade is what establishes the degree of darkness or lightness of green that is found in the gem. Natural emeralds can have a wide variety of green tones. These include: Very Light, Light, Medium Light, Medium, Medium
Generally speaking, a high quality emerald will have a tone that ranges from “Medium” to “Very Dark.” However, natural emeralds can fall into any of those tonal grade categories. The tonal grade alone can’t determine the true quality of an emerald. Hue and saturation also have to be considered.
Hue refers to the type of green color that an emerald has. It’s what gives the name to the color. For example, a natural emerald can be referred to as “bluish green,” or “yellowish green.” Most emeralds on the market today are Columbian, and Columbian emeralds present a “bluish green” color. Saturation, on the other hand, is what gives the color of an emerald its intensity and strength. Emerald saturation can range from a very dull green, to a pure vivid green. For example, “Medium Dark” stones are generally considered as high quality. However, if the stone has a boring and dull saturation, the overall quality of it is lowered. On the other hand, if a “Medium Light” stone is sparkling with vivid saturation, it will be more appealing. That’s why when grading emeralds based on their color, saturation and hue always have to be taken into consideration along with the tone.
Emerald Grading Scale
Emeralds are gemstones. Therefore, they can be graded by the preferred grading system for all gemstones. They can be placed into the categories Natural AAA, AA, or A.
- Natural AAA - This is the highest quality and best category that an emerald can be in. In terms of quality, they are the top 10% of gemstones. Natural AAA emeralds are rich green, moderately to slightly included, and they exhibit very high brilliance.
- Natural AA - This is the second best category for gemstones. Natural AA gemstones account for 20-30% of all gemstones. Emeralds in this category are medium green and moderately included
- Natural A - This category accounts for 50-75% of all gemstones. Natural A emeralds are dark green, heavily included, and opaque. They are still good, but they are considered to have the lowest quality compared to the two categories above
Apart from Natural AAA, AA, and A, there’s also a category that some emeralds are in called Heirloom/Rare Emerald. This is the highest quality, even better than AAA. They are very rare and expensive, though.
Emerald clarity refers to what the gemstone looks like on the inside. The clarity of emeralds makes them different from any other gemstone. Most emeralds have inclusions which include small bits of gasses, other minerals and crystals, and liquids that the emeralds take on during the crystallization process. It’s normal for emeralds to have inclusions - in fact, around 99% of all natural emeralds will include them. The Gemological Institute of America (GIA) has made three categories of clarity types for colored gemstones. They include Type 1, Type 2, and Type 3 gemstones. Emeralds naturally fall into the Type 3 gemstone category.
- Type 1 gemstones - These are typically inclusion-free, or almost inclusion-free
- Type 2 gemstones - These gemstones are usually included
- Type 3 gemstones - These are almost always included
Inclusions in Emeralds
Inclusions are normal in emeralds, but if there are too many, the gemstone will start to look less like a crystal. Also, too many inclusions can compromise how durable a stone is, and they can lower the value if they’re too close to the surface. Low clarity emeralds will have too many inclusions, especially ones close to the surface. However, it’s important to understand that inclusions are a natural part of emeralds, and you should always expect to find them. Inclusions in emeralds are special, and if an emerald doesn't have any inclusions it could be synthetic, or an imitation.
Since emeralds are naturally included, it has become standard practice to treat the stones with oils or resins in order to enhance their clarity. Cedar oil is the most common oiling technique used to improve emeralds clarity, therefore improving its overall quality and grade. Overall, emeralds are graded quite differently from other gemstones. Color, including hues, tones, and saturation, is the most important factor when determining their quality. The best grades of emeralds to use for jewelry are Natural AAA, followed by Natural AA.Shop Emerald Rings