Digital refractometer by Presidium (model Prim II) Digital scales - regular lines - resolution 0.001g Can be used anywhere

Can be used anywhere

Disadvantages over an optical refractometer:- it's not as versatile as an optical refractometer

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All about (and reviews of)  binocular (head-worn) magnifiers- especially the surgeons-type

Digital refractometer by Presidium (model Prim II) Digital scales - regular lines - resolution 0.001g Can be used anywhereSummary Made by Presidium, the leading manufacturers of gem testing equipment. There is downloadable software to connect it to your computer. The reading is then displayed along with a list of stones that match the reading, and you can click on each stone to see more information (constants). This saves time looking up charts. Comes with a USB cable (connects to any computer mobile device USB mains adaptor). Works with loose stones and also stones