Fracture Filling of Diamonds

There are many discussions on the issue of man made diamonds and diamond simulants and warnings not to be enticed by their prices but instead to focus your attention and get your wallet ready for natural diamonds only. However, even natural diamonds can be not that excellent when they are treated. It’s hard to find a perfect diamond without any flaw but when it happens the price for it skyrockets very high. Instead, it’s much easier to enhance the diamond by eliminating flaws. Fracture filling is one of the methods used for concealing imperfections. Forewarned is forearmed: read the article below to find more about the method in case you are considering over purchasing a diamond:

One relatively new diamond treatment that was developed to help in concealing a diamond’s flaws or making one appear whole is fracture filling. Fracture filling is sometimes a simple method for maintaining the existing diamond proportions, instead of breaking the stone apart.

This process involves the use of special glass formulas that possess a refractive index. This refractive index is similar to a diamond that was pioneered by Zvi Yehuda of Ramat Gan in the mid-1980s. Today, the term “Yehuda” is widely used as a brand name for fracture-filled diamonds. Fracture filling has joined long established techniques like surface coating as a method for concealing imperfections.

In the 1990s, Koss & Schechter, an Israel diamond company tried to substitute halogen-based glass in an attempt to modify the Yehuda process. Their attempt proved to be unsuccessful. A New York based company, Dialase, utilizes its own glass formula in performing fracture filling on diamonds. Fracture filling treatments cannot be used on diamonds that possess large cracks.

During the fracture filling process, a glass-like paste that shares the same optical properties and color as the diamond that will be filled is placed inside the diamond. This glass-like paste contains either bromide or a silicone based glass-like material. To the naked and untrained eye, the blemishes and flaws of the fracture-filled diamond are virtually invisible. Externally, it appears beautiful, clear and unblemished as any natural diamond would. This is due to the high refractive index of the glass-like paste used to fill the diamonds.

However, when a fracture-filled diamond is examined under a microscope by a trained gemologist with the use of the proper gemological instruments, air bubbles, filler glass flow lines, laser drilling marks, and other imperfections are seen. Bore holes and fractures are also sometimes evident. Laser drilling is a technique that is used to improve a diamond’s clarity through the removal of inclusions. Fracture-filled diamonds are also distinctive in that they give off a “flash effect” – that is, when the diamond is turned in another direction, flashes of colored light ranging from yellow to purple to orange to electric blue are seen.

The color varies depending on the current lighting conditions upon which the diamond is examined. One noteworthy feature of fracture-filled diamonds is the color of the glass. This color can range from yellow to brown and it has a significant impact on the overall color of the diamond. Additionally, because the glass used to fill fractures is not colorless, the treated stone’s color can be devalued by as much as a grade after undergoing diamond grading procedures at a diamond laboratory.

A comparatively low temperature of 1,400 degrees Celsius is sufficient to melt fracture fillings. This means that if a jeweler is not aware of the treatment conducted on the stone, a routine repair can cause a fracture-filled diamond to lose clarity or worse, shatter. This is why gemologists or jewelers need to be extremely careful when handling fracture filled diamonds. Setting or re-tipping the diamonds should be done with absolute precision and care to avoid inflicting any accidental damage to the diamond. Fracture filled diamonds should not be exposed to any form of acids. It is also possible for a fracture-filled diamond to disintegrate if placed in an ultrasonic cleaner.

The diamond treatment of fracture filling is a hotly debated topic in the diamond industry as well in the private sector due to the fact that the process is both radical and impermanent. If you are planning to purchase fracture filled diamonds, it is important that you are aware that they should not cost nearly as much as untreated diamonds that share the same weight, color and clarity. As a matter of fact, diamonds that have undergone fracture filling should cost approximately half the price of untreated diamonds.

Also, it is important for potential diamond buyers or investors to understand that tests have shown that fracture filled diamonds are prone to discoloration and may become cloudy after prolonged exposure to daylight. Looking on the bright side, new types of fillers have been developed by diamond laboratories in order to produce fracture filled diamonds that are less prone to color alteration or leak outs.

Many of the major gemological laboratories, including EGL International, do not issue certificates for fracture-filled diamonds. The World Jewellery Confederation and the US Federal Trade Commission have also set regulations stating that all fracture-filled diamonds must be identified as such during the time of sale.

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