Unlike all other natural gemstones, many emeralds have inclusions. It has become harder to get high quality emeralds that have not undergone treatments.

In fact, emeralds of the highest quality have internal crystal structures that are complex and called “garden-like inclusions.”

The inclusions in emeralds are usually ignored because of their unique bluish-green colour. Emeralds that have attractive defects are sold for similar prices to defect-free ones. But there are some cases where they cannot be ignored. In these cases, the internal gas bubbles, embedded crystals, as well as cracks, give the gem a cloudy or opaque appearance.

Why are emeralds treated?

Emeralds can be oiled in order to improve their appearance. This is because natural emeralds have tiny fissures and cracks before they are treated. They also sometimes have patches of dull colour that occur during the formation of the gem.

This is why natural emeralds are often treated with oil, resin, or wax. These are used to fill these fissures and give the emeralds a smooth and even surface. This is due to the fact that the oil-filled gem has the same light performance as the natural emerald.

Generally, emeralds are treated with natural oils. The most commonly used oil is cedarwood oil. Cedarwood oil is an excellent choice because it is colourless, and its refractive index is close to that of emerald. Cedarwood oil dries out and would need to be re-applied. The oiling process is not easy, and for this reason, another solution was found.

Before an emerald is re-oiled, it is important that all the old oil be removed. This can be removed by soaking the emerald in solvents such as alcohol or acetone, or simply simmering the stone slowly in soapy water.

1. Once all the old oil is removed, clean the emerald properly by using warm water and a soft cloth. If possible, remove the stone from any pendant or earring backs. Rub the damp cloth properly over the emerald until it is slightly bright and then allow it to dry off.
2. Ensure that you are using pure cedar oil that has not been mixed with other oils. Pour this oil into a small container and place the emerald inside as well. Turn it gently so that all the faces are coated properly. Add more oil until the emerald is covered by the oil.
3. Remove the emerald from the oil after 8 hours and place it gently on a folded cloth. Allow the oil to stay for about 24 hours so that it can enter all the fissures and seal them.
4. Wipe off the excess oil from the emerald.

Treatment with oils is temporary, and improper care of the stone will cause it to evaporate, change colour or leach out of the stone. The oil helps to hide flaws and improve the colour of the stone. They exist so as to be able to increase the appearance of the emerald to the eye.

How should I care for my emerald?

No matter natural or lab-grown emeralds like Biron Emeralds, they are very durable. They might not be as hard as diamonds or sapphires, but they are resistant to scratching. Because a large number of emeralds are treated with oil and resins, it is not advisable to use steam or ultrasonic cleaners. They can make the oils and resins dissolve and sweat off the stone.

The most effective way to clean an emerald is by using warm soapy water. The stone should not be soaked in soapy water, alcohol, acetone or paint thinner. Harsh detergent should be avoided as well. Here is the cleaning process:

1. Combine warm water and mild dish soap in a bowl. Put the emerald jewellery in the solution for about a minute.
2. Remove the oils and dirt that have accumulated on the piece by using a small toothbrush. More attention should be paid to the inside, avoiding brushing the top directly.
3. Rinse the jewellery completely in another bowl of warm water to remove any soapy residue.
4. Dry the jewellery properly with the use of a soft clean towel.

Conclusion

The major reason for oiling is to improve clarity or colour. Dye is occasionally added to the surface-reaching fissures to give lighter-coloured emeralds more colour. Despite this, the most common treatment for emeralds is oiling.

While large emeralds are relatively easy to oil, it might be better to leave small stones to the jeweller. Even emeralds that do not have fissures that reach the surface can be oiled effectively, just like those with surface-reaching fissures.