You may find inexpensive, Chinese-made, no brand, “no name” refractometers for sale online for around $150. With some new refractometers costing more than $500, these will certainly appeal to the cost conscious.
I’ve been anxious to try one of these. Fortunately, one of our IGS members lent us a unit to test.
When I opened the package, one difference was apparent immediately. The “no name” instrument was much smaller than my GIA Duplex II refractometer. (See the photo at the top of the article for a comparison). The hemisphere, lens, and light opening were less than half the size of the GIA unit. I expected this would cause problems. However, once I started my tests this turned out not to be the case.
First, I tested a number of identified faceted gems with established refractive indices (RI). To my surprise, I found the “no name” unit much easier to use than the larger Duplex II. The smaller hemisphere creates a smaller viewing area. Thus, the stone is centered automatically in the magnifying lens.
Compared to the Duplex II, this was a delight. With it, I usually start with the magnifying lens off. I get my…