2. PERFORMING A TEST with your Presidium
Refractive Index Meter II
Remove the cylinder and place a well-cleaned, polished
gemstone at the centre of the pad. Make sure that the
gemstone is well centered to prevent reading error
(Fig. 2.1).
Fig. 2.1
Cover the gemstone with the recessed cylinder (Fig. 2.2).
Fig. 2.2
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