Clarity Enhanced / Fracture Filled Diamonds:

The words "Clarity Enhanced" might lead you to believe that a diamond has been polished really well to enhance its brilliance, but I'll bet the words "Fracture Filled" woke you up!  The terms clarity enhanced and fracture filled tend to be used synonymously, but should be disclosed to the consumer in writing as "clarity enhanced / fracture filled".

The clarity enhancement process was developed in 1982 by Israeli inventor and diamond cutter Zvi Yehuda, and involves filling cracks in diamonds with molten glass to improve their clarity.  Clarity enhanced diamonds did not begin to appear in the market in substantial quantities until the 1990's.

It is important to note that many diamonds contain minute internal "cracks" that do not pose a threat to the integrity or life span of the diamond.  Retailers frequently refer to cracks as "feathers" because the term is less disturbing to their customers... We simple prefer to call a tree a tree and call a crack a crack...

Only diamonds with small cracks can be treated with the clarity enhancement.  The clarity enhancement process will not work for diamonds with large cracks.  The clarity enhancement process tends to improve a diamonds clarity by one grade and does not affect the color or weight of the diamond because only a thin glass film is used.

According to Yehuda, the "advantage" to clarity enhanced diamonds is their lower cost and that they create the potential for a person to purchase a larger, cleaner diamond than they would have otherwise been able to afford.

What are the disadvantages of buying a fracture filled diamond?  The GIA Gem Trade Laboratory (GTL) conducted an extensive study of fracture filled diamonds and published their results in the Fall 1994 issue of Gems & Gemology Magazine.  The GIA scientists concluded that "prolonged exposure - or numerous short exposures - to commonly employed cleaning methods may sometimes damage filling substances."  In addition, it was determined that "repolishing of jewelry and repair procedures involving direct exposure to heat (such as re-tipping of prongs) may damage and partially remove the filler from such treated diamonds."

OK, the disadvantages of buying a fracture filled diamond in English...  A diamond treated with the clarity enhancement process developed by Zvi Yehuda should hold up to every day wear and tear as well as an untreated diamond.  However, a jeweler working on a piece of jewelry that contains a clarity enhanced diamond should exercise care while setting or re-tipping the prongs that hold the diamond because the enhancement process can be damaged by temperatures in excess of fourteen hundred degrees and/or mild acids.  Jewelry repair procedures that do not involve direct heat on the diamond, such as sizing a ring, rarely damage the filling.  So, if you're going to cremate yourself or dive into a tub of boiling acid, take your ring off first!

Here's the good news, if in fact you purchase a Yehuda Clarity Enhanced / Fracture Filled Diamond and the treatment ever fails, any jeweler can send it back to Yehuda and they will re-treat your diamond for free, regardless of why the treatment failed.  When Yehuda first introduced the concept of clarity enhanced diamonds into the market, we were quite skeptical of not only the treatment but also of their guarantee. So we purchased a clarity enhanced diamond from Yehuda and promptly set it on fire.... We're talking Inferno!!!  Sure enough, at sixteen hundred degrees Fahrenheit the filling sizzled right out of the stone with a loud hiss and a pop!  We sent the diamond back to Yehuda along with a note that said "Whoops!" and a short time later the diamond was returned to us looking as good as new!  We still have it and use it as an example of what a Yehuda Treated diamond looks like even though we do NOT sell clarity enhanced diamonds.

Now, not all clarity enhanced diamonds are created equal and not all of them come with a guarantee.  Some companies use bromine to enhance their diamonds because the process is cheaper than using glass.  Diamonds treated with bromine have been known to discolor and cloud with exposure to the ultra violet radiation found in sunlight.  The Yehuda-treated diamonds tested by the scientists at the GIA - GTL did not show any changes when exposed to ultraviolet radiation.  You can be assured that you are buying a Yehuda fracture filled diamond because it comes with small white plastic card stating the Yehuda Guarantee.

But what if you don't want a fracture filled diamond?   How can you be sure the diamond you are buying has not been clarity enhanced?   It should be as simple as asking, but a trip through a local mall proved otherwise... We don't sell to mall jewelry stores so it was easy for us to walk into the mall stores and look at the diamonds they were selling.  Each of the stores denied selling clarity enhanced diamonds, and pointed across the mall to their competitor and said "but they do."  If only you could have seen the looks on their faces when we pointed to the flash effect in their diamonds and said "Then what's this?"

Despite FTC guidelines which require jewelers to disclose diamonds treated with the clarity enhancement process in writing to consumers as "Clarity Enhanced / Fracture Filled" many stores do not provide disclosure of any type to their unsuspecting customers.  An industry survey conducted in January of 1995 states that an estimated 72% of jewelers who sell clarity enhanced diamonds fail to provide disclosure to their consumers.  Sadly, the one's who do often only state that the diamond is clarity enhanced and don't mention the words fracture filled because they are afraid it will scare the consumer.

The good news is that purchasing a diamond certified by a reputable laboratory such as GIA, AGS, EGL-LA, HRD, CGL, Zenhokyo, etc. will prevent you from accidentally purchasing a clarity enhanced / fracture filled diamond... To the best of our knowledge, the only laboratory that certifies clarity enhanced / fracture filled diamonds at this time is European Gemological Laboratories (EGL) and in the event that a diamond is enhanced, it will be clearly stated in the "Comments" section of the certificate.  It is our understanding that all of the other major gemological laboratories refuse to certify clarity enhanced / fracture filled diamonds at this time.

clarity enhanced diamonds Now you may be wondering how you can detect a clarity enhanced diamond... Here's an upside down view of a round brilliant cut diamond that has been clarity enhanced using the Yehuda process.  Notice the electric purple-blue flashes in the middle of the stone. TRJ Photo.

This "flash effect" is typical of a Yehuda clarity enhanced diamond and does not appear in an untreated stone.  Here's another look at the same diamond from a side angle.

clarity enhanced diamonds The flash is more predominant and there is an abrasion visible just right of the flash on the girdle edge... It is important to note that the flash color varies depending on the lighting conditions used.   Common flash colors include violet, purple, pink, orange, green, and yellow. TRJ Photo.
clarity enhanced diamonds Uh oh, here's the same clarity enhanced diamond viewed face up.  Where's the flash effect?  It's not visible from this angle and herein lies the challenge of identifying a fracture filled diamond.   The flash effect is not visible from all angles and is frequently difficult to locate.  TRJ Photo.

By the way, this diamond is Clarity Enhanced / Fracture Filled to be of VS in clarity... That's proper disclosure.  All of the preceding photographs are of a Clarity Enhanced / Fracture Filled round brilliant cut diamond and were taken in our laboratory at Treasures by R.J. using bright field illumination and represent the diamond at 30x magnification.

Detecting clarity enhancement in unmounted diamonds is relatively easy, however mounted diamonds can be quite difficult because the mounting can obstruct your ability to view the diamond from all angles and tends to wash out the flash effect. For this reason, we recommend that you always inspect diamonds unmounted when clarity enhancement is a concern...

The clarity enhancement is easily detected by viewing the diamond against a dark field (black background) with light being directed in from the side of the diamond. You will most likely have to inspect the diamond from several different directions.  Characteristics which indicate that a diamond may be fracture filled include:

  • Flashes of Color:  Clarity enhanced diamonds treated by Yehuda in the 1980's displayed an orange flash when examined against a black background (dark field illumination).  The same treated area would flash blue when examined against a white background (bright field illumination). Diamonds treated recently by Yehuda flash violet purple to pink when examined using dark field illumination and green to yellow using bright field illumination.  Diamonds treated by other companies exhibit similar colors but they appear more saturated than those found in Yehuda treated diamonds.
  • Air Bubbles:  Most fracture filled diamonds contain air bubbles that have been trapped inside the filling.  In some cases they appear as tiny pinpoints and others may be quite large.
  • Cloudy Areas: Sections of white-cloud-like areas in a diamond may actually be tiny air bubbles trapped in a filled area.

If you detect a vivid, yet somewhat elusive, flash of color the diamond is probably clarity enhanced, but not necessarily.  Natural iridescence in an unfilled break or crack within a diamond can resemble the flash effect left by the clarity enhancement process.

If you are uncertain as to whether a diamond has been clarity enhanced / fracture filled, we recommend you have it examined by a qualified Graduate Gemologist who is not affiliated with the store you are dealing with.

More information on clarity enhanced / fracture filled diamonds