Fable R.I. Meter

Fable R.I. Meter

• Measuring Refractive Index (RI): The primary function is to measure the Refractive Index of faceted gemstones. Each gemstone variety has a unique RI, allowing for identification.
• Determining Optical Properties: It can distinguish between isotropic and anisotropic (uniaxial or biaxial) gemstones.
• Gemstone Identification: By comparing the measured RI with known values, the refractometer helps identify the gemstone material.
• Distinguishing Between Similar Gems: It helps differentiate between gemstones that look alike but have different refractive indices. 

• Measuring Range: 1.35-1.85 RI.
• Accuracy: ≤ ± 0.003.
• Testing Prism: High hardness synthetic cubic zirconia (CZ).
• Light Source: Built-in quasi-monochromatic LED light source (wavelength 589 ± 3 nm).
• Table: Stainless steel.
• Eyepiece: 32mm diameter, 4x magnification.
• Additional Features: Includes a polarizer, refractive index liquid, and can be powered by batteries or an external adapter. 

1. Prepare the Stone: Ensure the gemstone is clean and has a well-polished facet.
2. Apply RI Liquid: Place a tiny drop of refractive index liquid (usually 1.785 ± 0.005) on the hemicylinder (the testing prism).
3. Position the Gem: Place the gemstone table-down on the RI liquid and center it on the hemicylinder.
4. View and Read: Look through the eyepiece, adjusting your head until you see the shadow line on the internal scale. This is the RI reading.
5. Birefringence Testing: Rotate the polarizing filter to observe if the shadow edge moves or splits, indicating double refraction.