Treatment
The most common and practical treatment for emerald
is clarity enhancement, commonly referred to as
“oiling.” This process of clarity enhancement has
been known since antiquity. Due to its fissured and
fractured nature, emerald’s transparency is almost
always compromised. Historically, different types of
oils, waxes and resins have been used to mask the
surface reaching breaks in order to enhance the
clarity. In the last few decades, both liquid and
hardened polymers have been used. Clarity
enhancement can dramatically affect clarity and
transparency. Unlike heat treatment, oiling changes
the appearance but not structure. Emerald does not
respond well to heat treatment. Irradiation (to
improve color) is known but the results are uninspiring.
Natural Emeralds
In commerce, it is important to determine if an emerald is
treated since unenhanced gem quality material is very rare.
Rarity results in very high prices for untreated emeralds. The
majority of emeralds in the North American market have a
moderate level enhancement. However, during the past few years
the wealth accumulation market for finer quality emeralds has
experienced an increased demand for stones with “none” or
“minor” degree of enhancement. There are always buyers asking
only for stones with reports that will state no enhancement.
The price difference between treated and untreated natural
fine and extra fine emerald is substantial – as much as 500%
depending on size.
Pair of Emerald, Diamond and Pearl ear pendants. Each
suspends a pear-shaped emerald weighing approximately
23.34 and 23.18 carats.
Courtesy: Christie’s
Investment Considerations
It is generally less challenging for the gemologist/appraiser to
determine that a particular stone has been treated, than to
determine that it is untreated. Emerald is priced by assessing
the color, clarity, cut, quality, transparency and weight of the
stone. Enhancement can dramatically affect clarity and transparency. Since the 2008 recession, prices for
untreated emeralds have increased substantially! The price structure for fine quality emerald is projected to
continue increasing. It is important to remember when investing in emeralds to look for only Natural AGL
Certified Untreated Gem Stones. They provide the best opportunity for Wealth Appreciation, Preservation of
Capital and Global Liquidity!
5
Emerald
Untreated Columbian Emerald Ring 4.17 Carats