Spinel Specialist Mini Course
Fracture Filling Spinel Treatments
In the gem trade, fracture filling is frequently used to improve the clarity of many different gemstones. Although spinels are usually clean and free of flaws, some specimens have fractures that can be filled.
Essentially, fracture filling a spinel involves applying an oil or resin with a refractive index similar to the gemstone. The fluid fills in surface-reaching fractures and can drastically reduce the appearance of any gaps. Fracture filling can also make the color distribution within the gem seem more uniform.
Please note that fracture filling may improve a spinel’s clarity grade but doesn’t boost its durability.
Identifying a Fracture-Filled Spinel
A simple microscope examination is the best way to determine whether a spinel has been fracture filled. Tiny gas bubbles often become trapped in the filler within the gem during the filling procedure. Free-floating gas bubbles don’t occur in natural spinels. So, if you see even one through your microscope, look at the surrounding area carefully. If there is no filler and the bubble is embedded in…
Emily Frontiere is a GIA Graduate Gemologist. She is particularly experienced working with estate/antique jewelry.
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