Natural Emeralds vs Lab Created Emeralds
As emerald is one of the most expensive gemstones, lab created emeralds are quite common in the market today. Therefore it is important to know how to differentiate the two.
Almost all natural emeralds contains inclusions and natural emeralds free of inclusions are super expensive. All average natural emeralds contains a significant amount of inclusions, more than other gemstone precious verities. Therefore, when buying natural emeralds, color is the most important factor and clarity is not as important as for other gemstones.
Even though natural inclusions in emeralds do not affect the price as much as for other gemstones, those serve the important purpose of identifying natural emeralds from lab created emeralds.
Inclusions of Natural and Lab Created Emeralds
There are several differences between natural and lab created emeralds, appearance wise and composition wise.
The difference in appearance is mainly due to the inclusions of natural emeralds. However, with the advancement of technology, the lab created emeralds also have inclusions and it requires a trained eye to distinguish between natural emerald inclusions and synthetic emerald inclusions. Some people still believe that lab created emeralds do not contain inclusions. This belief is not true any longer.
Natural Emerald Inclusions
These are small fractures inside the gemstone. Also called feathers, these do not impact the look of the stone unless there are a significant amount. They look like lines or feathers inside the stone.
These are also liquid filled bubbles inside the stone. The appearance of this inclusion type is the reason for its name.
Cavities and Chips
Outline of a crystal shape cavity within the emerald are called cavities. The actual crystal is not present but it has left this cavity.
Tube looking inclusions which run parallel to each other.
Trapped water inside the stone during the formation of the gemstone appears as twisting inclusions.
Certain parts of emerald can appear white or transparent, forming color zones. This is called color zoning. It is the duty of the cutter to make the green look even across the gemstone.
Lab Created Emeralds
The two of the popular methods of creating synthetic emerald are flux-melt and hydrothermal methods.
Refractive indices of flux-melt emerald are 1.561 to 1.564 or 1.565. This is a fraction below the lowest value for natural emeralds from Colombia. Specific gravity of flux-melt emerald is about 2.65, 2.66, which is also different to 2.71 of natural Colombian emerald.
In terms of inclusions, both flux-melt and hydrothermal emeralds usually contain fingerprint like inclusions. Those are filled with solid flux in flux-melt emeralds and with liquid and gas in hydrothermal emeralds.
Lab created emeralds also show a red fluorescence under ultraviolet detectable under long wave radiation.