KM or Internal Laser Drilling. KM means "special drilling" in Hebrew, "Kiduah Miuhad." If you want to ask: why is it necessary to invent another kind of laser drilling? Is conventional laser drilling not enough to eliminate inclusion? The answer is simple. Laser Drilling does good work, but it's easily detectable because of the drilled channel. Even regular jewelers can detect laser drilling by the look from the side. Instead of it, KM works differently, and sometimes it's isn't easy to identify this kind of treatment. Let's see how it works. The unfocused laser beam heats the dark inclusion inside the diamond.

The process of inclusion's heating inside the diamond creates internal pressure. This process is similar to the function inside another kitchen appliance – the pressure cooker, with a small but significant difference. There is no steam vent to release the pressure from inside the stone. So, the pressure finds itself the way out, breaking and splitting the diamond and creating the artificial fracture. The next step after the treating is deep boiling of the stone in strong acids to dissolve the inclusion and burned carbon residues inside the fracture.

In some cases, after the treatment, only the professional gemologist can detect this kind of clarity enhancement. If the artificial fracture is not too wide, the dirt from outside will not penetrate the stone. Generally, the treatment is not bad, but it is mostly applied to shallow clarity diamonds. So even after the treatment, the diamond remains non-attractive.

The third and most popular method of clarity enhancement is Fracture Filling. The diamond's fracture stops the ray of light, traveling through the stone like a barrier. The crack became light, and as a result, it is visually noticeable. How to make it "disappear" or less visible, at least? One of the diamantaires discovered that fractures could be easily filled with glass. We also call it silicone or silicate, but they are just different names for the same material. Filling with high refractive index glass makes fracture appear much less visible. Diamonds look much cleaner. This procedure can turn the unsellable I2 clarity diamond into desirable SI1. Under normal conditions, fracture filling is stable for some time. But it is easily damaged under the heat, pressure, or acids environment of kitchen chemical cleaners, degreasers, removers, and descalers. The regular procedure of cleaning the jewelry set with a fracture-filled diamond using standard jeweler's devices and methods is not recommended. Ultrasonic, steamer, or cleaning liquids will damage the filling. Over time, due to extended exposure to the sun's ultraviolet rays, the transparency of the filer inside the fractures deteriorates. It may dry out and appear milky or dirty. In this case, the filler should be removed and refilled with a new one. It is up to every person to choose or not to choose a clarity-enhanced diamond for her ring. I am personally would not advise you to purchase clarity-enhanced diamonds. If you wish to buy a good stone and save some money, I recommend looking for color-enhanced HPHT-treated stone, Bombardier, or laboratory-grown diamonds.