Treated Diamonds

Many jewelers treat diamonds to command a better price for them. Some treatments are permanent, while others are just temporary. While the treatment may enable the jeweler to command a higher price, this is only based on what the consumer sees with the naked eye.

In fact, treating a diamond actually lowers its value. Therefore, you need to let the jeweler know that you are informed, and simply ask if the diamond has been treated. In fact, you can get a notarized statement from your jeweler stating that the diamond is not treated. Many states in the US now require jewelers to tell you if a diamond is treated, even if you do not ask.

There are several different treatments that may be used, and you need to know what they are, so that you can spot them. A diamond may be filled for clarity, irradiated for color, or painted for color.

When a diamond is filled for clarity, the inclusions (imperfections) are filled with glass. This makes the diamond appear clearer. This is a permanent treatment; however the glass can be damaged by heat, cleaning, or by re-tipping. Furthermore, the glass does not actually repair the inclusion. It simply makes it less noticeable.

You can tell if a diamond is filled by turning it around under sunlight. As you rotate it, you may see a blue flash. This is an indication that the diamond has been filled. A diamond may also be laser drilled to remove inclusions.

A diamond can be irradiated to change its color. This is done with the use of radium salts. While it may make the diamond look nice, the irradiation can be affected by heat, ruining the color of the diamond later on. This is, however, also considered a permanent treatment.

We discussed painting a diamond earlier, when we mentioned that some disreputable jewelers will apply a dot of color on the tip of the diamond. This is a temporary treatment. It will be gone within days of your purchase.

While it isn’t as common anymore, a mounted diamond may be treated with colored foil. The diamond is mounted in a closed back setting, and there is colored foil between the diamond and the setting. Often, the only way to see the foil is with a magnifying glass or microscope. When moisture gets between the diamond and the setting, the foil will become damaged or fade.

Foil has largely been replaced, however, with the use of violet blue dyes and vacuum sputtered films. This treatment is used to make a more yellow diamond appear white.