Glass Filled Ruby

Treatment: Fracture Filling

Identification Tools Required: Magnification.

How to Identify: 

Primary Test: Anyone who has been in the gemstone business for a while knows that there has been a huge influx of cheap rubies into the market in the last few years. The reason: a lot of corundum material that was previously unsalable due to extreme fracturing has been made salable by using the same fracture filling process used for diamonds. The key method of identifying this material is the very unusual appearance of the rubies under magnification. The first issue is the flash effect that imparts a bluish color to the ruby, far beyond anything normal. The blue flash is a diagnostic feature of this filler material. Also, the milky appearance of the gemstone will give a strong indication that filler material is present as a natural ruby will not have this type of milky appearance.

Another magnification “tell” is the surface crackling of the gemstones. One type of filler uses a leaded glass material that also coats the surface of the stone. With normal wear and tear this surface will get a crackled effect of broken glass because….well it is basically broken glass on the surface. As seen below this is a classic diagnostic feature of a fill treated ruby.

And finally, gas bubbles. Sometimes HUGE gas bubbles that are unlike anything natural. These are also diagnostic as they are usually far larger than anything that would naturally be present in an untreated ruby.

Secondary Tests: None needed

Repair and Setting: Absolutely no heat can be applied to these stones. And no cleaners or ultrasonics. If damaged the stones cannot be repaired. Jewelers are urged to take every precaution with this material including information consumers BEFORE any work is attempted that you are not responsible for any damages. All work should be noted in advance that it is at consumer risk. Stones can be set carefully but cracking and breaking is a major problem. Bottom line is that any ruby in today’s market should be considered treated until otherwise proven.