The stones have a very faint light blue color and few inclusions. Through closer inspection under a microscope, we determined the stones are definitely not diamonds, but were unsure of exactly what mineral they are.
All gemstones have multiple identifying characteristics. For instance, color is an easily seen characteristic. The type of inclusions, a stone's specific gravity, its crystal habit and fracture type and other things like refractive index and optic character are also used to identify stones. Because characteristics like color and fracture type can be the same in multiple gemstones, we have to look at all of them in combination.
In this case, our next step was to determine the stone's refractive index, which is the speed of light traveling through the stone versus light traveling through the air. Through the refractometer, we were able to narrow the stones down to a few minerals, but still were unsure.
We then used a polariscope to determine whether it was singly or doubly refractive and to determine its optic character.
Benitoite and chrysoberyl were possibilities, but based on all our findings, we found the gemstone to be corundum. Sapphires and rubies are varieties of corundum, and the mineral comes in nearly every color. Although our customer's gemstones don't look like a typical sapphire, they could be referred to as colorless sapphires.
Many gemstones are very easy for our trained gemologists to identify without this multi-step process, but we always find the detective work fun when we are presented with a stone such as this.
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A gemstone or gem also called a precious or semi-precious stone, or jewel is a piece of mineral, which, in cut and polished form, is used to make jewelry or other adornments.
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