A jewelry loupe is probably not what you expect. You don’t string beads on it or wear it around your neck. In fact, a loupe is a special magnifier that professional jeweler’s use to closely examine gemstones (yes, exactly like the ones you’ve seen in all of those diamond-heist films). But there is a lot more to a loupe than a simple magnifying glass. It must have the proper lens, particular fittings, and a select range of magnification in order to accurately grade diamonds and gemstones.
There are two different types of lenses available for a loupe: a single or a triplet. The single, as you may have guessed, contains only one lens. While this is probably fine for amateurs, it can both distort your view of the stone and generate flashes of light (or color) that make it hard to determine the quality. For pros, this cannot happen since they are engaged in certification. Therefore, most professional jewelers use a triplet (which naturally has three lenses) to eliminate visual interference of any kind. In addition, the fittings (or framing) on the lenses should be black. This way, colors from light will be absorbed so that they don’t impede the appraisal.
Finally, any jeweler who’s worth his salt will tell you that, despite the wide range of magnifications available in the loupe world, there is one that is correct. Now, the right magnification could vary depending on the eyesight of the jeweler, but most would agree that ten times magnification (denoted by “10X” on the casing of the loupe) is preferable. Lower magnifications may miss certain elements necessary to determine the specifications of the stone while levels higher than ten may show interesting features that unfortunately cannot be included in the appraisal (making them moot).
Of course, amateur gemologists may not be willing to shell out the cash for a truly fine loupe, but they are an absolute necessity for the professional jeweler. So if you’re just getting into the business, be sure to find a proper loupe (or even a couple of different quality for comparison purposes) to ensure that the diamonds and gemstones you appraise are really worth what you say they are.
