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Glass-filled rubies

August 13, 2021

Glass-filled rubies

To be able to distinguish between untreated rubies and those that have been glass-filled or otherwise treated is an essential skill for any potential buyer of rubies. The fact is the cost of a gem is highly dependent on the type of treatment. Exceptionally high price: $10,000 per carat for unheated natural rubies. And $1 per carat for the glass-filled rubies that are massively on the market today. Thus, there is always a chance to buy glass-filled rubies at a high price, but how to distinguish them so as not to overpay?

First of all, you must understand what you are searching for and confirm the stone genuine by the certificate's authenticity. If the seller did not tell you what kind of treatment the stone was subjected to, this could be considered a fraud. But there are also cases when there is simply no certificate, or it has not yet been produced. Therefore, today you have the opportunity to learn more about what is composite rubies. We sincerely wish this guide will give you a basic knowledge of how to differentiate between treatments. In this article, you will learn in more detail about what distinguishes natural stones from composite gemstones that have undergone glass-filled treatment. We will also tell you about the alternative treatment, which is the most common today.

What is a composite ruby?

a composite ruby

The most common method of enriching rubies today is glass filling, as a result of which the so-called composite ruby is born. This is a technology for filling the voids with a stone with glass melt. It is used in places where rubies are mined. It is common knowledge that rubies are precious stones that are rarely found in nature without defects. Natural rubies contain mineral inclusions, gas-liquid and gas bubbles, cavities, voids. These inclusions and defects sometimes occupy 30-50-70% of the stone volume. There are even stones that are almost opaque.

However, all this can be corrected with this method of refining stones. Composite gemstones always look cleaner than they really are, with a more intense color than they have before. But in fact, such specimens do not carry great value. The cost of glass rubies cannot exceed 25-30 per carat. Therefore, it is worth being able to distinguish this type of refinement from others.

A true ruby ​​that has not been treated is easy to recognize. The main thing is to find natural inclusions in the gem. They can be seen through a microscope and an ordinary magnifying glass with 10x magnification.

These include such as:

  • boehmite needles;
  • angular, straight, or hexagonal growth zoning;
  • direct, angular and possible color zoning, color stripe;
  • intact mineral inclusions, possibly opaque, which may have angular edges;
  • undamaged two-phase connections.

Glass-filled rubies should have gas bubbles. They are normally very simple to spot under a microscope or magnifying glass. Also, a key indicator of lead glass-filled rubies, the blue and orange flash effect along with structural fractures.

What is heat treatment?

Heat treatment is the most widespread treatment method used for rubies, sapphires, tanzanite, zircon, topaz, tourmaline, and many other stones. It improves the clarity and/or shade of the stones. Heat treatment rubies cost an order of magnitude higher than glass-filled ones and cannot be lower than 100 per carat with very low quality. Rubies, pure by eye, start at 500 per carat and up, depending on color and weight. And this price has several reasons to be.

heat treatment

Firstly, heat treatment is completely normal for the gemological community, since in the overwhelming majority of cases, its result is permanent. Composite gemstones, on the other hand, become fragile and unstable in wear. And secondly, such treatment of ruby ​​allows you to dissolve mineral inclusions in the liquid natural way contained in the stone. By filling the stone with molten glass, it simply squeezes out everything that is possible from the stone through cracks and pores, gluing them at the end of the process creating a “hybrid gem” in the weight of which there may be more glass than the ruby itself.

But, before giving this high price, it is better to make sure that the ruby ​​you are buying has not been subjected to any other treatments. For ruby ​​testing, you can get a GRS certificate. It will indicate that the ruby ​​was only H-treated or H (a). If it says H (b) or below, then you will comprehend that the stone ​​has been subjected to other treatments. And so you won’t have to pay for it like you would for a regular ruby.

We hope that our short guide helped you understand what a composite ruby is. Use only trusted sites in order not to run into scammers and not to purchase glass-filled rubies for fabulous money. If you want to acquire only natural rubies and specimens that have undergone heat treatment, then you can look into the Gem Lovers catalog.

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