Fissure Filled Rubies, Also Called Glass Filled Rubies. What Are Fissure Filled Rubies?
Natural gems including rubies are always found in a rough form. The gems are cut and polished before being set in jewelry or sold as loose gems. Natural rubies like all other natural stones will have inclusions and fissures (cracks) within the stone. Rubies are expensive gems and you will have to accept the fact that, these flaws will in most cases be visible to the naked eye. Over the years, gem manufacturers have studied and tested various treatments that can be used to better the appearance of natural gems. Ruby is one gem that has been heat treated for many decades, this treatment is used for almost 95% of the rubies that reach the gem and jewelry markets. Gem experts accept this treatment since, it does not affect the durability of the gemstone. The enhancement that heat treatment does on the clarity and color of the ruby is permanent.
As the years went buy, large scale ruby mining depleted the mines. The rough ruby that was brought up from the mines was not only decreasing in quantity but also in quality. In every mining trip, some of the ruby gems are so bad that conventional heating cannot improve the condition of the stone. It was normally the junk ruby that was either thrown away or made into low value carvings and objects. Gem manufacturers experimented for years hoping to find a way to better the appearance of this very low grade ruby stones.
A few years ago, they came up a process that was set to revolutionalize the gemstone industry. At least that was what the founders hoped for. Absolutely low quality rubies that were almost totally opaque with heavy inclusions and fissures were the starting point of this dream story. The rubies derived after the treatment were called 'fissure filled' rubies but the name 'glass filled' rubies might have been a better choice. Here is how the rubies are treated by this process, we have tried to keep the explanation as simple and non-technical as possible.
Acid Wash: Very low grade rubies are soaked and washed in a strong acid solution. This process causes the gem to become somewhat porous and also brittle. Rubies are normally very hard gems, second only to diamonds. But the acid wash makes them lose this hardness. The stones can be easily broken after the acid wash. This is the first stage in the fissure filling process of rubies.
Heating: Conventional heat treatment of rubies is done without adding any chemicals into the oven. But in the process used to fissure fill rubies, silica (glass) salts are added to the crucible that contains the rubies. The oven temperature is turned way up and this causes the silica salts to melt and become molten. The flowing glass (melted silica) goes through the now porous ruby rough and also fills the fissures and cracks in the stone. The glass also helps to 'hold' the brittle gem stone together. Since the treatment causes cracks in the ruby gem stone to be filled, it is referred to as the 'fissure filling' process. Remember that the melting silica actually forms glass and seeps through the cracks, the resulting rubies are therefore sometimes called 'glass filled' rubies.
Cutting and Polishing: The rubies are taken out of the oven and left to cool. The stones that earlier appeared opaque and awful now resemble red glass, the clarity and color is drastically enhanced. Gem cutters then proceed to cut and polish these fissure filled rubies.
The above paragraphs give a clear view of the steps followed to treat rubies by the fissure filling process. We will now discuss how the treatment affects (positively or negatively) the rubies that are put through the process.
Color and Clarity: The color and clarity of the treated rubies is highly enhanced. The stones look gorgeous, if you wanted to get such a gem through the conventional heating treatment, you would end up paying at least 100 to 150 times more!
Durability: By nature, rubies are extremely durable. They boast of a hardness factor of 9, making them a wee bit less harder than diamonds. You should know that diamonds are the hardest gems to be used in conventional jewelry. However all this durability and hardness deserts the fissure filled ruby. Fissure filled rubies are infact composite stones that combine corrundum (ruby mineral) and plain glass. The stones can scratch or chip easily. Even a simple thing like using an ultrasound cleaner can ruin glass filled rubies.
Price Comparison: To make this comparison clear, we need to compare 'similar' looking gems. We are actually trying to compare the price of conventionally heated rubies and glass filled rubies. Take a 3 carat heat treated ruby and a 3 carat fissure filled ruby with similar external appearance. The fissure filled ruby would be priced at around 15 U.S$ to 25 U.S$ for the piece. A similar (external appearance) ruby with conventional heat treatment would be priced at around 2,000 U.S$ to 2,500 U.S$ for the piece. However you need to keep in mind that, fissured filled rubies are very low on durability too.
If you wish to buy a glass filled ruby, it would be a good idea to keep the contents of this report in mind. For a gem seller, there is no problem in selling such rubies as long as the buyer is kept fully informed of all the facts. The worst case scenario for the buyer is when he gets tricked into buying one of these low quality fissure filled rubies but pays for a good conventionally heated ruby! The only way to avoid such sad situations is to choose the right jeweler, so make sure that you do sufficient searching and checking before choosing your jeweler.
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