Clarity and Diaphaneity in Zambian Emeralds
In 2008, commercial mining of Zambian Emeralds began. To compete with the belief among consumers that Colombian Emeralds are the best quality to be had, Zambian Emeralds not only had to match their quality, but had to surpass them. So could they do it? What does a Zambian Emerald have that a Colombian does not?
All Emeralds have unique inclusions running through the gem. This is true of Emeralds from anywhere in the world, including Zambia.
However, due to the unique chemical fingerprint of Emeralds from this location, the beauty of these inclusions (known as jardin) is enhanced. To understand why, we must first understand clarity and diaphaneity and the difference between the two.
What is clarity?
You may have heard of clarity as being one of the ‘Four Cs’ by which a Diamond is judged. Clarity is simply the absence of inclusions. The cleaner the gem, the more light can pass through the gem. Emeralds are a Type 3 gemstone, which means that they aren’t expected to have good clarity and this is accepted.
What is diaphaneity?
It is actually the differences in diaphaneity that make or break an Emerald. This is an under-used term – with all the focus on the memorable ‘4 Cs’, one of the most important value factors of any gem – diaphaneity – is almost completely overlooked.
So what is it? Diaphaneity is not a new idea. Gemmologists as separated by time and space as Chinese Admiral Zheng He, Tavernier (of Hope Diamond fame) and Benjamin Zucker referred to it as the ‘water quality’ of a gemstone. Diaphaneity is the quality of a gemstone’s crystal structure. The more perfect the crystal structure, the better the gemstone acts a medium for light to travel through. In layman’s terms, this is the difference between a crystal clear Diamond and an opaque Lapis Lazuli. A good example of a gem with poor clarity but good diaphaneity is Rutile Quartz. The rutiles within the gem mean it has poor clarity by definition, but the finest examples will have great transparency through the rest of the gem. This means it has good diaphaneity but poor clarity.
How does diaphaneity affect beauty?
If a gem has good diaphaneity it means that the light travelling through the gem will be unimpeded – there will be a clearer path for the light to travel through the gem. This means that more light will be refracted back up through the table facet (the top surface of the gem), giving the gem more brilliance. It also means that more light will leave the gem through dispersion, which gives a gem its sparkling rainbow of colours.
When we consider Emerald in this way, it is easy to see why diaphaneity is so important. In a gem that is almost always included, the difference in quality can be measured in the gem’s diaphaneity. Not only does greater diaphaneity yield more brilliance for the observer, but it also enhances the beauty of an Emerald’s jardin, allowing an unimpeded view of the inclusions suspended within the gem. Just as the finest examples of Rutile Quartz allow you to see the rutile needles without any cloudiness or obstruction, the same is true of an Emerald’s jardin. These extraordinary inclusions are ‘Mother Nature’s fingerprint’ and allow us to identify our unique Emerald amongst an entire parcel of matched gemstones.
What makes Zambian Emeralds so beautiful?
Zambian Emeralds faced some incredible competition from other sources when they emerged on the market. Colombian Emeralds held the monopoly at the luxury end of the market. To compete, Zambian Emeralds had to do something Colombian Emeralds could not. This difference is diaphaneity. By having superior diaphaneity, Zambian Emeralds allow you to better appreciate your Emerald’s jardin. This difference is found in the crystal structure of Emeralds from Zambia.
To understand why Zambian Emeralds have such a unique crystal structure, we must reach back through to time to when that crystal structure was forming.
Read part 3 here or shop Zambian Emerald here.
