November 13th, 2019

What is the difference between Dublir and Fracture Filling in the diamond? Clarity Enhanced diamonds

First of all let's find out what fracture filling means?
The supply of diamonds in nature is great. However, not all diamonds have good clarity and visibility.
Over the years, scientists have tried different ways to improve the visual appearance of the stone.
Today we have several technics to enhance the clarity of the diamond or with the simple words: to make it look better.
This time, we will focus on improving the clarity of the diamond with the help of fillers (CLARITY ENHANCED BY FRACTURE FILLING).
We'll take a close look at this kind of clarity treatment and will find out how to detect it easily.
First of all, let's ask: why do we have to enhance the clarity of the diamonds? To make an additional profit?
No. We have to treat and to improve the clarity of low-quality diamonds, that cannot be sold in "as is" condition.
We have to make it look attractive enough to be sold to a customer. So, how does it works?
In the process of filling the Glatz (cracks or fractures in the professional language), we infuse foreign material into those cracks that reach the surface.
The action allows the beams of light moving inside the stone to advance in a uniform middle with optical properties close to the "host" diamond and therefore the glitter is not shiny, less prominent and less visible to the beholder.

In simple words: empty Glatz (fracture) is visible, fracture filled with glass becomes much less visible and in some cases - almost invisible.
The process of filling the glaciers began in the 1980s. It has undergone changes and improvements since that time.
Today we notice two types of fillers: regular filler ("blue") and special filler ("red")

In both cases, a foreign matter is introduced into the cracks and voids that reach the surface. The operation must be done under high pressure and high temperature. However, before inserting the filling material into the open cracks, the diamond must undergo a process of deep-acid boiling under the pressure.
Deep boiling cleans and removes foreign materials and dirt, trapped in the open crack.
The successful filling is contingent on good cleaning of the fracture. We must also remember that during the process of "deep boiling", the fracture may open and expand. It's rare but it may happen.
At the beginning people used a filler based on lead - we call it "Regular Filling". The inserted material was durable but it caused the diamond's color to decrease in three to four degrees on the color scale. Dilution of the filler material helped to reduce the effect of the color decrease.
The regular filling is almost colorless. The normal filling is suitable for tight, narrow spaces and not "catches" in the case of open slots.
The treated stone appears to have less life and shine.
The lack of regular refilling is in its response to prolonged exposure to sunlight and especially to ultraviolet rays. Exposure of the filler material to ultraviolet rays (such as the diamond exposure to sun rays in the shop window) causes the filler material to blacken. It looks browner and damages the diamond's look.
Nowadays "Special Filling" is mostly used on the basis of silicon glass material. The filling is extremely durable and is especially suitable for non-thin and narrow open gels.
Please note: Deep boiling takes out the filling material and returns it to the original condition. However, the regular filling cames out faster.
The cleaning of the diamond with ultrasonic penetrates the gletz and the filling may be damaged, though the regular filling will be more damaging.
Exposing the filler to home detergents (dish soap, floor cleaners, or hot water) does not necessarily affect the filler.

Now the most important is the following: how can we find out that diamond was enhanced by fracture filling?

It can be easily done with the help of a regular loupe, microscope or another mignifying device.

We just have to keep in mind the simple rule. To detect the filling we have to look at the fracture under the angle close to 45 degrees.

This is an example of the fracture filled diamond by 45 degrees view.

Please note: It is very hard to notice the treatment if you look at the fracture under the angle close to 90 degrees.

This is an example of the fracture filled diamond under 90 degrees angle view. Fracture filling is almost invisible.

In some cases you can easily detect fracture filling with the gemological microscope in shadows mode:

Now we will talk about a very important issue. The "Dublir"

Sometimes, gletz with fracture filling can be confused with "Dublir" or "Dublirung".
Why can it be important? It is simple, Fracture Filling is a treatment technique.
It means that the clarity of the diamond was enhanced and it dramatically reduced the value of the diamond.
Dublir is not a treatment, it is just an optical effect of light refraction and it doesn't reduce the value of the stone.
So, how does "Dublir" looks like?
Dublir is just the effect when we see the play of colors inside the glatz without any kind of filling inside the fracture.
Now comes the question: If there is no filling inside the fracture why do we see the play of colors?
Well, in this case, we can ask: why we can see the rainbow in the sky after the rain?
it's just the refraction of regular "white" light into containing colors inside the gletz or inside the cloud as in the case of the rainbow.
Let's see how the dublir looks like?

Take a closer look:

Now let's ask the most important question: how to differ Dublir and Fracture Filling?

There are two major differences between dublir and fracture filing:

1. Dublir. Colors inside the Gletz (fracture) are not of blue or pink tints, like in the case of fracture filling.
Colors inside the dublir look similar to the colors of the rainbow:

2. Colors in Dublir are visible under 90 degrees view. Fracture filling almost invisible under 90 degrees veiw.
As we know fracture filling is visible by 45 degrees view.
So if we see the colors inside the gletz:
1. Under 90 degrees view
2. Not blue or pink but all the colors of the rainbow
It means, that we see Dublir and there is no Fracture Filling inside the gletz (fracture).

And if we see blue or pink colors inside the gletz by 0 to 45 degrees angle view, (not by 90 degrees angle) it means that it's Fracture Filling treatment.

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By Semyon Felshyn G.G. GCI
The founder of the: