Diamonds come into contact with a number of elements during their formation in the ground and these contribute towards their impurities or imperfections. Trapped air is one such element. Even if a diamond is cut and polished to perfection, the trapped air bubble would still be visible to the naked eye by the way light is refracted by this pocket of air. The pockets of air resemble cracks or fissures inside the diamond. These imperfections can greatly reduce the appeal of the rock and hence the price.
The process of fracture filling was invented by an Israeli scientist in the 70’s. This process involves the use of a clear glass like substance which is forced into the diamond through the fissures. This glass like material refracts and reflects light just like a diamond would and hence the diamond would look somewhat perfect. This process makes the pockets of air disappear and the diamond would seem perfect to the naked eye and sometimes even under a microscope.
The filler does not alter a diamonds weight. The diamond still retains all its qualities in terms of color, shape and carat weight but the clarity improves by one or two grades. The highest attainable grade for a fracture filled diamond is VS2 and the diamond appears better and hence the value increases.
Normal wear and tear will not remove the filler from a fracture filled diamond. This however is still a temporary treatment and certain circumstances can remove the filler and cause the diamond to retain it original look. A jeweler’s torch or acid can cause the filler to evaporate. However most treatment lab will guarantee their work and in these rare cases they will refill the diamond at no extra cost.
A professional jeweler is able to tell if a diamond has undergone fracture filling. There is a flash effect that can be seen when light goes through the filler material. These flashes are brilliant colors that are apparent on rotating the diamond. These flashes are not apparent when the diamond is viewed form the face up position. They are apparent when the diamond is viewed from the bottom.
Fracture filled diamonds caused a huge controversy when they were introduced into the US since some jeweler were fleecing customers by selling them at the price of flawless diamonds without revealing that they had undergone any enhancement.
Today, these types of diamonds are readily sold and accepted by buyers as long as the jeweler discloses that they are enhanced diamonds.