How does the emerald grading system determine the difference between a rare, high-quality emerald and a more common one?
Emeralds are one of the most coveted gemstones there are. To better understand their value and the characteristics of a “good” emerald, accredited gemological societies have created a grading system to classify them.
Type I, II, and III Emeralds
The established emerald grading system follows three types: Types I, II, and III.
Type I gemstones form with incredible clarity. They have almost no inclusions visible to the naked eye. In layman’s terms, inclusions are small imperfections in a gemstone that, even when present, are acceptable and don’t necessarily make a gemstone less valuable.
Type II gemstones have some inclusions present but are minimal.
Type III gemstones almost always have inclusions. Emeralds are considered a Type III gemstone, and so oftentimes, are oiled for increased clarity. Type III can further be broken down into four additional categories of VVS (very, very slightly included), VS (very slightly included), and SI1 and SI2 (small inclusions). VVS is the most sought after.
Emerald Inclusions: Nature’s Unique Signature
As mentioned, inclusions in emeralds are not always signifiers of “defects.” They are even used as identifying marks that make it easier to differentiate one emerald from another. Think of this as a unique ID system. When it comes to aesthetics, gemologists and jewelers have come to refer emerald inclusions as “gardens.” They can resemble foliage growth inside a gemstone, giving it a garden-like appearance from within.
Consider as well that this is simply how emeralds organically occur in nature. They are categorized according to this grading system that allows inclusions because of where they can come from: pegmatite rocks.
How Emeralds Are Formed in Nature
Pegmatites can only form when exposed to overwhelmingly high temperatures; they begin as one kind of rock, and when exposed to extreme heat and pressure from magma, undergo a process of transforming into a completely different kind of rock. A mix of components of magma are left behind in the environment in its final stage of cooling.
Pegmatites are also rich in beryllium, an alkaline metal which helps gives rise to the mineral beryl. When the right substances from cooling magma remain, they then mix with beryl. The mixture settles into the veins and crevices of pegmatite deposits, where emerald formations may be created and found. Pegmatite deposits are very mineral-dense and are composed of large crystals rarely found in other rocks, given the precise geological conditions under which they are created. These complex processes where magma combines minerals and other deep-earth substances are why emeralds are expected to have inclusions, and why they are not considered defects.
Natural vs. Synthetic Emeralds
Those seeking emeralds with zero inclusions may find what they’re looking for in synthetic lab-grown emeralds instead. While there are natural emeralds that may form without inclusions, they are very rare and sell for incredibly high prices.
Caring for Emeralds with Inclusions
A word of caution for owners of emeralds, especially those with a good number of inclusions: handle these gemstones with care, because they are less durable. Expert jewelers will understand that these kinds of emeralds should not be over-handled, especially when cutting them to fit into certain kinds of settings. In fact, jewelers may even refuse to store emeralds of this quality or accept commissioned work using them because they are difficult to handle and are prone to damage.
Consult a Professional Jewelry Appraiser
Consult a professional jewelry appraiser who has the updated knowledge and understanding to help you better care for your pieces. They can also provide you a better valuation of the gem should you want to buy, sell, or pass it on as an heirloom.
