More than any other gemstone, natural emeralds have a tendency to have many internal inclusions, tiny surface cracks, and fissures (internal cracks) throughout the gemstone. As a result, it has become a common practice in the industry is to have these emeralds treated with cedar oil or opticon to improve their appearance. As a buyer it is important to know which treatment was used on the emerald you are considering. This could save you some money and will help you purchase a stone that will retain its value over many years to come.
The most commonly used oil to treat an emerald is cedar oil. First, the emerald is cleaned in an acid bath, than placed in an airtight cylinder with heated cedar oil. The emerald is left to soak up the cedar oil for several hours, after which it is cooled and cleaned. This treatment does not last forever. Eventually the treated emerald will require another cedar oil bath to keep up its good looks. Throughout the lifespan of the emerald this process will have to be repeated several times.
In the 1980’s emeralds mined and produced in Brazil were being filled with a plastic substance called opticon. Opticon is an epoxy resin that is used to fill any fissures in a similar way the cedar oil is used. In same cases, the opticon is dyed green to artificially enhance the color of the stone. The problem with this method is that opticon has an expanding effect over a long period of time. This means that initial smaller fissures could be expanded over many years as a result of the opticon filler, which will ultimately affect the value of your emerald long term.
How do you know?
A treated emerald will look perfect to the naked eye, which makes identifying which emerald is treated difficult for the buyer. To help combat this problem, the GIA has developed a classification scheme that identifies the enhancement level of the emerald: how many fissures the natural emerald has, and what was used to treat the emerald. The US Federal Trade Commission also requires dealers to disclose if the emerald has been treated and with what chemicals. As a buyer, the first question you should ask the jeweler is “has this emerald been treated, and if so, which treatment?”
A Little Oil Never Hurt Anyone
Just because the emerald is treated does not mean that is not good. In some ways, this could work to the buyer’s advantage. The cost savings on a treated emerald is significant versus a naturally perfect stone. Cedar oil is the most respected treatment for emeralds and should not be feared. Opticon treatment, on the other hand, does not have the same respect within the jewelry industry. It is worth a conversation with your jeweler to determine which is the right gemstone for you.
At Jonathan’s Fine Jewelers, we have a vast inventory of non-treated and treated emeralds. Viewing these emeralds in person under an industrial grade microscope is the best way to be sure you are getting the best value for your dollar. Also, ask questions. An educated buyer is the best buyer. To schedule an appointment, click here.