Refractometer

How to use it

1. Place one small drop of contact liquid (RI ~1.80) on the hemicylinder
2. Lay a polished flat facet directly onto the hemicylinder
3. Look through the eyepiece toward a bright white light
4. Read where the shadow edge falls on the scale, this is the RI
5. Rotate the stone 90° and read again, if different, record both values
6. Birefringence = higher reading minus lower reading
7. Compare results to gem reference tables