Gem Identification (Part I)

Everyday gem identification work begins with a sorting pad, stone tongs, millimeter gauge, and a 10x power magnifier commonly known as a loupe (pronounced loop). Loupes come in different magnifications and apertures. The standard for gem identification and diamond grading is 10 times magnification. I prefer loupes with large apertures as they allow a greater amount of light to enter the lens. The lens is actually composed of 3 glass lens cemented together called a triplet lens. The loupe is CORRECTED for what is known as spherical and chromatic aberration. To the trained eye many gemstones can be identified at first sight under this level of magnification. Gemstones that are not conclusively identified at first sight then undergo a series of non-destructive optical tests that render identity a certainty. It is basically a process of elimination.