Optical Properties
Interactive tools for optical testing including dichroscope interpretation, polariscope reactions, refractometer reading practice, and pleochroism reference.
Dichroscope Results
Input observed colors to identify dichroic gem candidates
Polariscope Guide
Interpret isotropic vs anisotropic reactions
Interactive guide to interpreting polariscope reactions. Select a reaction pattern to learn more.
Testing Procedure
Set Up
Cross the polarizers so no light passes through
Rotate top polarizer until the field goes completely dark
Place Stone
Insert the gem between crossed polarizers
Use a bezel setter or immersion cell if needed
Rotate Stone
Rotate the stone 360° and observe changes
Count how many times it goes from light to dark
Interpret
Match the observed reaction to the patterns below
Some gems may show weak or partial reactions
Reaction Patterns
Important Notes
- • Optic axis: Stones viewed down optic axis remain dark even if anisotropic
- • Thin sections: Very thin stones may show weak reactions
- • ADR: Strain patterns indicate heat treatment or synthetic origin in some cases
- • Conoscope: Use convergent light to see interference figures
Troubleshooting
- • If no reaction at all, check polarizers are properly crossed
- • Weak reactions may need immersion fluid to reduce surface reflections
- • Multiple orientations needed for comprehensive testing
- • Clean polarizers and stone surface for best results
Refractometer Simulator
Practice reading shadow edges on a virtual scale
Practice reading refractometer shadow edges. Select a gem to simulate its reading on the scale.
Refractometer Scale View
Reading Tips
- • Single shadow edge: Isotropic gem (cubic or amorphous)
- • Double shadow edge: Doubly refractive gem - rotate to see both
- • Blurry edge: Poor contact with hemisphere - add RI fluid
- • No reading: RI above 1.81 (over the limit)