Covid-19 Opening hours update 12th April 2021: Gem-A Instruments is open for delivery, Click & Collect, and pre-booked on-site shop appointments.
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Refractometers and Accessories

The refractometer measures the refractive index (RI) of a gem material. Safe and suitable for most polished gemstones, it is an invaluable gemmological tool –no gemmologist should be without one! With it, you can measure the minimum and maximum RI values, observe optic character and calculate any birefringence. We sell RI fluids which will take readings up to 1.81 and our refractometer comes with a built-in monochromatic filter (sodium yellow) for taking clear readings.