Refractometer Guide, Part 2: Cabochon Testing
Step 3: Practical Gemology
Table of Contents
You can use a refractometer to determine the refractive indexes (RI) of most cabochons and carved gems. If your test gems have a flat, polished bottom, your cabochon testing proceeds as with any faceted gem. If not, you can take a spot reading.
Finding a Cabochon Refractive Index
To test a gem with a curved surface:
- Clean the stone thoroughly.
- Next, set up your refractometer without the magnifying lens in place.
- Place a very small amount of RI fluid on the hemicylinder, then