Presidium Digital GEM Refractometer (PRIM II) - Measures RI Value for Diamond & Moissanite

This refractometer works great! However if you’re not experienced gemologist or jeweler, it’s not going to magically identify your stones. First off you have to learn to move the flat faceted parts of the stone around to see exactly what •range• of readings you’re getting. Taking just one reading isn’t enough. Then you use the card that’s included to identify the stone. I was able to easily separate real diamond melee from moissanite melee using this tool, for example. You also need to use it with the large cap or in a darkened area to prevent stray light from altering the measurements. Its ability to record RI over 2.0 is very useful. Overall it’s the best refractometer for the money.